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version 1.1.1.2, 2014/06/15 16:31:38	version 1.1.1.5, 2023/09/27 11:02:08
Line 1	Line 1
.TH DNSMASQ 8	.TH DNSMASQ 8 2021-08-16
.SH NAME	.SH NAME
dnsmasq \- A lightweight DHCP and caching DNS server.	dnsmasq \- A lightweight DHCP and caching DNS server.
.SH SYNOPSIS	.SH SYNOPSIS
Line 27 TFTP server to allow net/PXE boot of DHCP hosts and al	Line 27 TFTP server to allow net/PXE boot of DHCP hosts and al
.PP	.PP
The dnsmasq DHCPv6 server provides the same set of features as the	The dnsmasq DHCPv6 server provides the same set of features as the
DHCPv4 server, and in addition, it includes router advertisements and	DHCPv4 server, and in addition, it includes router advertisements and
a neat feature which allows nameing for clients which use DHCPv4 and	a neat feature which allows naming for clients which use DHCPv4 and
stateless autoconfiguration only for IPv6 configuration. There is support for doing address allocation (both DHCPv6 and RA) from subnets which are dynamically delegated via DHCPv6 prefix delegation.	stateless autoconfiguration only for IPv6 configuration. There is support for doing address allocation (both DHCPv6 and RA) from subnets which are dynamically delegated via DHCPv6 prefix delegation.
.PP	.PP
Dnsmasq is coded with small embedded systems in mind. It aims for the smallest possible memory footprint compatible with the supported functions, and allows uneeded functions to be omitted from the compiled binary.	Dnsmasq is coded with small embedded systems in mind. It aims for the smallest possible memory footprint compatible with the supported functions, and allows unneeded functions to be omitted from the compiled binary.
.SH OPTIONS	.SH OPTIONS
Note that in general missing parameters are allowed and switch off	Note that in general missing parameters are allowed and switch off
functions, for instance "--pid-file" disables writing a PID file. On	functions, for instance "--pid-file" disables writing a PID file. On
Line 42 the configuration file.	Line 42 the configuration file.
Read and syntax check configuration file(s). Exit with code 0 if all	Read and syntax check configuration file(s). Exit with code 0 if all
is OK, or a non-zero code otherwise. Do not start up dnsmasq.	is OK, or a non-zero code otherwise. Do not start up dnsmasq.
.TP	.TP
	.B \-w, --help
	Display all command-line options.
	.B --help dhcp
	will display known DHCPv4 configuration options, and
	.B --help dhcp6
	will display DHCPv6 options.
	.TP
.B \-h, --no-hosts	.B \-h, --no-hosts
Don't read the hostnames in /etc/hosts.	Don't read the hostnames in /etc/hosts.
.TP	.TP
.B \-H, --addn-hosts=<file>	.B \-H, --addn-hosts=<file>
Additional hosts file. Read the specified file as well as /etc/hosts. If -h is given, read	Additional hosts file. Read the specified file as well as /etc/hosts. If \fB--no-hosts\fP is given, read
only the specified file. This option may be repeated for more than one	only the specified file. This option may be repeated for more than one
additional hosts file. If a directory is given, then read all the files contained in that directory.	additional hosts file. If a directory is given, then read all the files contained in that directory
	in alphabetical order.
.TP	.TP
	.B --hostsdir=<path>
	Read all the hosts files contained in the directory. New or changed files
	are read automatically and modified and deleted files have removed records
	automatically deleted.
	.TP
.B \-E, --expand-hosts	.B \-E, --expand-hosts
Add the domain to simple names (without a period) in /etc/hosts	Add the domain to simple names (without a period) in /etc/hosts
in the same way as for DHCP-derived names. Note that this does not	in the same way as for DHCP-derived names. Note that this does not
apply to domain names in cnames, PTR records, TXT records etc.	apply to domain names in cnames, PTR records, TXT records etc.
.TP	.TP
.B \-T, --local-ttl=<time>	.B \-T, --local-ttl=<time>
When replying with information from /etc/hosts or the DHCP leases	When replying with information from /etc/hosts or configuration or the DHCP leases
file dnsmasq by default sets the time-to-live field to zero, meaning	file dnsmasq by default sets the time-to-live field to zero, meaning
that the requester should not itself cache the information. This is	that the requester should not itself cache the information. This is
the correct thing to do in almost all situations. This option allows a	the correct thing to do in almost all situations. This option allows a
Line 64 time-to-live (in seconds) to be given for these replie	Line 77 time-to-live (in seconds) to be given for these replie
reduce the load on the server at the expense of clients using stale	reduce the load on the server at the expense of clients using stale
data under some circumstances.	data under some circumstances.
.TP	.TP
	.B --dhcp-ttl=<time>
	As for \fB--local-ttl\fP, but affects only replies with information from DHCP leases. If both are given, \fB--dhcp-ttl\fP applies for DHCP information, and \fB--local-ttl\fP for others. Setting this to zero eliminates the effect of \fB--local-ttl\fP for DHCP.
	.TP
.B --neg-ttl=<time>	.B --neg-ttl=<time>
Negative replies from upstream servers normally contain time-to-live	Negative replies from upstream servers normally contain time-to-live
information in SOA records which dnsmasq uses for caching. If the	information in SOA records which dnsmasq uses for caching. If the
Line 81 the upstream DNS servers.	Line 97 the upstream DNS servers.
.B --max-cache-ttl=<time>	.B --max-cache-ttl=<time>
Set a maximum TTL value for entries in the cache.	Set a maximum TTL value for entries in the cache.
.TP	.TP
	.B --min-cache-ttl=<time>
	Extend short TTL values to the time given when caching them. Note that
	artificially extending TTL values is in general a bad idea, do not do it
	unless you have a good reason, and understand what you are doing.
	Dnsmasq limits the value of this option to one hour, unless recompiled.
	.TP
.B --auth-ttl=<time>	.B --auth-ttl=<time>
Set the TTL value returned in answers from the authoritative server.	Set the TTL value returned in answers from the authoritative server.
.TP	.TP
	.B --fast-dns-retry=[<initial retry delay in ms>[,<time to continue retries in ms>]]
	Under normal circumstances, dnsmasq relies on DNS clients to do retries; it
	does not generate timeouts itself. Setting this option
	instructs dnsmasq to generate its own retries starting after a delay
	which defaults to 1000ms. If the second parameter is given this controls
	how long the retries will continue for
	otherwise this defaults to 10000ms. Retries are repeated with exponential
	backoff. Using this option increases memory usage and
	network bandwidth.
	.TP
.B \-k, --keep-in-foreground	.B \-k, --keep-in-foreground
Do not go into the background at startup but otherwise run as	Do not go into the background at startup but otherwise run as
normal. This is intended for use when dnsmasq is run under daemontools	normal. This is intended for use when dnsmasq is run under daemontools
Line 95 don't change user id, generate a complete cache dump o	Line 127 don't change user id, generate a complete cache dump o
SIGUSR1, log to stderr as well as syslog, don't fork new processes	SIGUSR1, log to stderr as well as syslog, don't fork new processes
to handle TCP queries. Note that this option is for use in debugging	to handle TCP queries. Note that this option is for use in debugging
only, to stop dnsmasq daemonising in production, use	only, to stop dnsmasq daemonising in production, use
.B -k.	.B --keep-in-foreground.
.TP	.TP
.B \-q, --log-queries	.B \-q, --log-queries
Log the results of DNS queries handled by dnsmasq. Enable a full cache dump on receipt of SIGUSR1.	Log the results of DNS queries handled by dnsmasq. Enable a full cache dump on receipt of SIGUSR1. If the argument "extra" is supplied, ie
	.B --log-queries=extra
	then the log has extra information at the start of each line.
	This consists of a serial number which ties together the log lines associated with an individual query, and the IP address of the requestor.
.TP	.TP
.B \-8, --log-facility=<facility>	.B \-8, --log-facility=<facility>
Set the facility to which dnsmasq will send syslog entries, this	Set the facility to which dnsmasq will send syslog entries, this
Line 112 running, will go exclusively to the file.) When loggin	Line 147 running, will go exclusively to the file.) When loggin
dnsmasq will close and reopen the file when it receives SIGUSR2. This	dnsmasq will close and reopen the file when it receives SIGUSR2. This
allows the log file to be rotated without stopping dnsmasq.	allows the log file to be rotated without stopping dnsmasq.
.TP	.TP
	.B --log-debug
	Enable extra logging intended for debugging rather than information.
	.TP
.B --log-async[=<lines>]	.B --log-async[=<lines>]
Enable asynchronous logging and optionally set the limit on the	Enable asynchronous logging and optionally set the limit on the
number of lines	number of lines
Line 133 can be over-ridden with this switch.	Line 171 can be over-ridden with this switch.
.TP	.TP
.B \-g, --group=<groupname>	.B \-g, --group=<groupname>
Specify the group which dnsmasq will run	Specify the group which dnsmasq will run
as. The defaults to "dip", if available, to facilitate access to	as. The default is "dip", if available, to facilitate access to
/etc/ppp/resolv.conf which is not normally world readable.	/etc/ppp/resolv.conf which is not normally world readable.
.TP	.TP
.B \-v, --version	.B \-v, --version
Line 145 to zero completely disables DNS function, leaving only	Line 183 to zero completely disables DNS function, leaving only
.TP	.TP
.B \-P, --edns-packet-max=<size>	.B \-P, --edns-packet-max=<size>
Specify the largest EDNS.0 UDP packet which is supported by the DNS	Specify the largest EDNS.0 UDP packet which is supported by the DNS
forwarder. Defaults to 4096, which is the RFC5625-recommended size.	forwarder. Defaults to 1232, which is the recommended size following the
	DNS flag day in 2020. Only increase if you know what you are doing.
.TP	.TP
.B \-Q, --query-port=<query_port>	.B \-Q, --query-port=<query_port>
Send outbound DNS queries from, and listen for their replies on, the	Send outbound DNS queries from, and listen for their replies on, the
Line 153 specific UDP port <query_port> instead of using random	Line 192 specific UDP port <query_port> instead of using random
that using this option will make dnsmasq less secure against DNS	that using this option will make dnsmasq less secure against DNS
spoofing attacks but it may be faster and use less resources. Setting this option	spoofing attacks but it may be faster and use less resources. Setting this option
to zero makes dnsmasq use a single port allocated to it by the	to zero makes dnsmasq use a single port allocated to it by the
OS: this was the default behaviour in versions prior to 2.43.	OS: this was the default behaviour in versions prior to 2.43.
.TP	.TP
	.B --port-limit=<#ports>
	By default, when sending a query via random ports to multiple upstream servers or
	retrying a query dnsmasq will use a single random port for all the tries/retries.
	This option allows a larger number of ports to be used, which can increase robustness
	in certain network configurations. Note that increasing this to more than
	two or three can have security and resource implications and should only
	be done with understanding of those.
	.TP
.B --min-port=<port>	.B --min-port=<port>
Do not use ports less than that given as source for outbound DNS	Do not use ports less than that given as source for outbound DNS
queries. Dnsmasq picks random ports as source for outbound queries:	queries. Dnsmasq picks random ports as source for outbound queries:
when this option is given, the ports used will always to larger	when this option is given, the ports used will always be larger
than that specified. Useful for systems behind firewalls.	than that specified. Useful for systems behind firewalls. If not specified,
	defaults to 1024.
.TP	.TP
	.B --max-port=<port>
	Use ports lower than that given as source for outbound DNS queries.
	Dnsmasq picks random ports as source for outbound queries:
	when this option is given, the ports used will always be lower
	than that specified. Useful for systems behind firewalls.
	.TP
.B \-i, --interface=<interface name>	.B \-i, --interface=<interface name>
Listen only on the specified interface(s). Dnsmasq automatically adds	Listen only on the specified interface(s). Dnsmasq automatically adds
the loopback (local) interface to the list of interfaces to use when	the loopback (local) interface to the list of interfaces to use when
Line 173 or	Line 227 or
options are given dnsmasq listens on all available interfaces except any	options are given dnsmasq listens on all available interfaces except any
given in	given in
.B \--except-interface	.B \--except-interface
options. IP alias interfaces (eg "eth1:0") cannot be used with	options. On Linux, when
.B --interface	.B \--bind-interfaces
or	or
.B --except-interface	.B \--bind-dynamic
options, use --listen-address instead. A simple wildcard, consisting	are in effect, IP alias interface labels (eg "eth1:0") are checked, rather than
of a trailing '*', can be used in	interface names. In the degenerate case when an interface has one address, this amounts to the same thing but when an interface has multiple addresses it
	allows control over which of those addresses are accepted.
	The same effect is achievable in default mode by using
	.B \--listen-address.
	A simple wildcard, consisting of a trailing '*',
	can be used in
.B \--interface	.B \--interface
and	and
.B \--except-interface	.B \--except-interface
Line 192 and	Line 251 and
.B --except-interface	.B --except-interface
options does not matter and that	options does not matter and that
.B --except-interface	.B --except-interface
options always override the others.	options always override the others. The comments about interface labels for
	.B --listen-address
	apply here.
.TP	.TP
.B --auth-server=<domain>,<interface>\|<ip-address>	.B --auth-server=<domain>,[<interface>\|<ip-address>...]
Enable DNS authoritative mode for queries arriving at an interface or address. Note that the interface or address	Enable DNS authoritative mode for queries arriving at an interface or address. Note that the interface or address
need not be mentioned in	need not be mentioned in
.B --interface	.B --interface
Line 202 or	Line 263 or
.B --listen-address	.B --listen-address
configuration, indeed	configuration, indeed
.B --auth-server	.B --auth-server
will overide these and provide a different DNS service on the	will override these and provide a different DNS service on the
specified interface. The <domain> is the "glue record". It should	specified interface. The <domain> is the "glue record". It should
resolve in the global DNS to a A and/or AAAA record which points to	resolve in the global DNS to an A and/or AAAA record which points to
the address dnsmasq is listening on. When an interface is specified,	the address dnsmasq is listening on. When an interface is specified,
it may be qualified with "/4" or "/6" to specify only the IPv4 or IPv6	it may be qualified with "/4" or "/6" to specify only the IPv4 or IPv6
addresses associated with the interface.	addresses associated with the interface. Since any defined authoritative zones are also available as part of the normal recusive DNS service supplied by dnsmasq, it can make sense to have an --auth-server declaration with no interfaces or address, but simply specifying the primary external nameserver.
.TP	.TP
.B --local-service	.B --local-service
Accept DNS queries only from hosts whose address is on a local subnet,	Accept DNS queries only from hosts whose address is on a local subnet,
ie a subnet for which an interface exists on the server. This option	ie a subnet for which an interface exists on the server. This option
only has effect is there are no --interface --except-interface,	only has effect if there are no \fB--interface\fP, \fB--except-interface\fP,
--listen-address or --auth-server options. It is intended to be set as	\fB--listen-address\fP or \fB--auth-server\fP options. It is intended to be set as
a default on installation, to allow unconfigured installations to be	a default on installation, to allow unconfigured installations to be
useful but also safe from being used for DNS amplification attacks.	useful but also safe from being used for DNS amplification attacks.
.TP	.TP
Line 256 addresses appear, it automatically listens on those (s	Line 317 addresses appear, it automatically listens on those (s
access-control configuration). This makes dynamically created	access-control configuration). This makes dynamically created
interfaces work in the same way as the default. Implementing this	interfaces work in the same way as the default. Implementing this
option requires non-standard networking APIs and it is only available	option requires non-standard networking APIs and it is only available
under Linux. On other platforms it falls-back to --bind-interfaces mode.	under Linux. On other platforms it falls-back to \fB--bind-interfaces\fP mode.
.TP	.TP
.B \-y, --localise-queries	.B \-y, --localise-queries
Return answers to DNS queries from /etc/hosts which depend on the interface over which the query was	Return answers to DNS queries from /etc/hosts and \fB--interface-name\fP and \fB--dynamic-host\fP which depend on the interface over which the query was
received. If a name in /etc/hosts has more than one address associated with	received. If a name has more than one address associated with
it, and at least one of those addresses is on the same subnet as the	it, and at least one of those addresses is on the same subnet as the
interface to which the query was sent, then return only the	interface to which the query was sent, then return only the
address(es) on that subnet. This allows for a server to have multiple	address(es) on that subnet and return all the available addresses otherwise.
	This allows for a server to have multiple
addresses in /etc/hosts corresponding to each of its interfaces, and	addresses in /etc/hosts corresponding to each of its interfaces, and
hosts will get the correct address based on which network they are	hosts will get the correct address based on which network they are
attached to. Currently this facility is limited to IPv4.	attached to. Currently this facility is limited to IPv4.
Line 271 attached to. Currently this facility is limited to IPv	Line 333 attached to. Currently this facility is limited to IPv
.B \-b, --bogus-priv	.B \-b, --bogus-priv
Bogus private reverse lookups. All reverse lookups for private IP ranges (ie 192.168.x.x, etc)	Bogus private reverse lookups. All reverse lookups for private IP ranges (ie 192.168.x.x, etc)
which are not found in /etc/hosts or the DHCP leases file are answered	which are not found in /etc/hosts or the DHCP leases file are answered
with "no such domain" rather than being forwarded upstream.	with "no such domain" rather than being forwarded upstream. The
	set of prefixes affected is the list given in RFC6303, for IPv4 and IPv6.
.TP	.TP
.B \-V, --alias=[<old-ip>]\|[<start-ip>-<end-ip>],<new-ip>[,<mask>]	.B \-V, --alias=[<old-ip>]\|[<start-ip>-<end-ip>],<new-ip>[,<mask>]
Modify IPv4 addresses returned from upstream nameservers; old-ip is	Modify IPv4 addresses returned from upstream nameservers; old-ip is
Line 285 are re-written. So	Line 348 are re-written. So
.B --alias=192.168.0.10-192.168.0.40,10.0.0.0,255.255.255.0	.B --alias=192.168.0.10-192.168.0.40,10.0.0.0,255.255.255.0
maps 192.168.0.10->192.168.0.40 to 10.0.0.10->10.0.0.40	maps 192.168.0.10->192.168.0.40 to 10.0.0.10->10.0.0.40
.TP	.TP
.B \-B, --bogus-nxdomain=<ipaddr>	.B \-B, --bogus-nxdomain=<ipaddr>[/prefix]
Transform replies which contain the IP address given into "No such	Transform replies which contain the specified address or subnet into "No such
domain" replies. This is intended to counteract a devious move made by	domain" replies. IPv4 and IPv6 are supported. This is intended to counteract a devious move made by
Verisign in September 2003 when they started returning the address of	Verisign in September 2003 when they started returning the address of
an advertising web page in response to queries for unregistered names,	an advertising web page in response to queries for unregistered names,
instead of the correct NXDOMAIN response. This option tells dnsmasq to	instead of the correct NXDOMAIN response. This option tells dnsmasq to
fake the correct response when it sees this behaviour. As at Sept 2003	fake the correct response when it sees this behaviour. As at Sept 2003
the IP address being returned by Verisign is 64.94.110.11	the IP address being returned by Verisign is 64.94.110.11
	.TP
	.B --ignore-address=<ipaddr>[/prefix]
	Ignore replies to A or AAAA queries which include the specified address or subnet.
	No error is generated, dnsmasq simply continues to listen for another reply.
	This is useful to defeat blocking strategies which rely on quickly supplying a
	forged answer to a DNS request for certain domain, before the correct answer can arrive.
.TP	.TP
.B \-f, --filterwin2k	.B \-f, --filterwin2k
Later versions of windows make periodic DNS requests which don't get sensible answers from	Later versions of windows make periodic DNS requests which don't get sensible answers from
the public DNS and can cause problems by triggering dial-on-demand links. This flag turns on an option	the public DNS and can cause problems by triggering dial-on-demand links. This flag turns on an option
to filter such requests. The requests blocked are for records of types SOA and SRV, and type ANY where the	to filter such requests. The requests blocked are for records of type ANY
requested name has underscores, to catch LDAP requests.	where the requested name has underscores, to catch LDAP requests, and for
	\fBall\fP records of types SOA and SRV.
.TP	.TP
	.B --filter-A
	Remove A records from answers. No IPv4 addresses will be returned.
	.TP
	.B --filter-AAAA
	Remove AAAA records from answers. No IPv6 addresses will be returned.
	.TP
.B \-r, --resolv-file=<file>	.B \-r, --resolv-file=<file>
Read the IP addresses of the upstream nameservers from <file>, instead of	Read the IP addresses of the upstream nameservers from <file>, instead of
/etc/resolv.conf. For the format of this file see	/etc/resolv.conf. For the format of this file see
Line 322 been built with DBus support. If the service name is g	Line 398 been built with DBus support. If the service name is g
provides service at that name, rather than the default which is	provides service at that name, rather than the default which is
.B uk.org.thekelleys.dnsmasq	.B uk.org.thekelleys.dnsmasq
.TP	.TP
	.B --enable-ubus[=<service-name>]
	Enable dnsmasq UBus interface. It sends notifications via UBus on
	DHCPACK and DHCPRELEASE events. Furthermore it offers metrics
	and allows configuration of Linux connection track mark based filtering.
	When DNS query filtering based on Linux connection track marks is enabled
	UBus notifications are generated for each resolved or filtered DNS query.
	Requires that dnsmasq has been built with UBus support. If the service
	name is given, dnsmasq provides service at that namespace, rather than
	the default which is
	.B dnsmasq
	.TP
.B \-o, --strict-order	.B \-o, --strict-order
By default, dnsmasq will send queries to any of the upstream servers	By default, dnsmasq will send queries to any of the upstream servers
it knows about and tries to favour servers that are known to	it knows about and tries to favour servers that are known to
Line 334 it will send queries to just one server. Setting this	Line 421 it will send queries to just one server. Setting this
dnsmasq to send all queries to all available servers. The reply from	dnsmasq to send all queries to all available servers. The reply from
the server which answers first will be returned to the original requester.	the server which answers first will be returned to the original requester.
.TP	.TP
	.B --dns-loop-detect
	Enable code to detect DNS forwarding loops; ie the situation where a query sent to one
	of the upstream server eventually returns as a new query to the dnsmasq instance. The
	process works by generating TXT queries of the form <hex>.test and sending them to
	each upstream server. The hex is a UID which encodes the instance of dnsmasq sending the query
	and the upstream server to which it was sent. If the query returns to the server which sent it, then
	the upstream server through which it was sent is disabled and this event is logged. Each time the
	set of upstream servers changes, the test is re-run on all of them, including ones which
	were previously disabled.
	.TP
.B --stop-dns-rebind	.B --stop-dns-rebind
Reject (and log) addresses from upstream nameservers which are in the	Reject (and log) addresses from upstream nameservers which are in the
private IP ranges. This blocks an attack where a browser behind a	private ranges. This blocks an attack where a browser behind a
firewall is used to probe machines on the local network.	firewall is used to probe machines on the local network. For IPv6, the
	private range covers the IPv4-mapped addresses in private space plus
	all link-local (LL) and site-local (ULA) addresses.
.TP	.TP
.B --rebind-localhost-ok	.B --rebind-localhost-ok
Exempt 127.0.0.0/8 from rebinding checks. This address range is	Exempt 127.0.0.0/8 and ::1 from rebinding checks. This address range is
returned by realtime black hole servers, so blocking it may disable	returned by realtime black hole servers, so blocking it may disable
these services.	these services.
.TP	.TP
.B --rebind-domain-ok=[<domain>]\|[[/<domain>/[<domain>/]	.B --rebind-domain-ok=[<domain>]\|[[/<domain>/[<domain>/]
Do not detect and block dns-rebind on queries to these domains. The	Do not detect and block dns-rebind on queries to these domains. The
argument may be either a single domain, or multiple domains surrounded	argument may be either a single domain, or multiple domains surrounded
by '/', like the --server syntax, eg.	by '/', like the \fB--server\fP syntax, eg.
.B --rebind-domain-ok=/domain1/domain2/domain3/	.B --rebind-domain-ok=/domain1/domain2/domain3/
.TP	.TP
.B \-n, --no-poll	.B \-n, --no-poll
Line 364 Tells dnsmasq to never forward A or AAAA queries for p	Line 463 Tells dnsmasq to never forward A or AAAA queries for p
or domain parts, to upstream nameservers. If the name is not known	or domain parts, to upstream nameservers. If the name is not known
from /etc/hosts or DHCP then a "not found" answer is returned.	from /etc/hosts or DHCP then a "not found" answer is returned.
.TP	.TP
.B \-S, --local, --server=[/[<domain>]/[domain/]][<ipaddr>[#<port>][@<source-ip>\|<interface>[#<port>]]	.B \-S, --local, --server=[/[<domain>]/[domain/]][<server>[#<port>]][@<interface>][@<source-ip>[#<port>]]
Specify IP address of upstream servers directly. Setting this flag does	Specify upstream servers directly. Setting this flag does
not suppress reading of /etc/resolv.conf, use -R to do that. If one or	not suppress reading of /etc/resolv.conf, use \fB--no-resolv\fP to do that. If one or more
more
optional domains are given, that server is used only for those domains	optional domains are given, that server is used only for those domains
and they are queried only using the specified server. This is	and they are queried only using the specified server. This is
intended for private nameservers: if you have a nameserver on your	intended for private nameservers: if you have a nameserver on your
network which deals with names of the form	network which deals with names of the form
xxx.internal.thekelleys.org.uk at 192.168.1.1 then giving the flag	xxx.internal.thekelleys.org.uk at 192.168.1.1 then giving the flag
.B -S /internal.thekelleys.org.uk/192.168.1.1	.B --server=/internal.thekelleys.org.uk/192.168.1.1
will send all queries for	will send all queries for
internal machines to that nameserver, everything else will go to the	internal machines to that nameserver, everything else will go to the
servers in /etc/resolv.conf. An empty domain specification,	servers in /etc/resolv.conf. DNSSEC validation is turned off for such
	private nameservers, UNLESS a
	.B --trust-anchor
	is specified for the domain in question. An empty domain specification,
.B //	.B //
has the special meaning of "unqualified names only" ie names without any	has the special meaning of "unqualified names only" ie names without any
dots in them. A non-standard port may be specified as	dots in them. A non-standard port may be specified as
part of the IP	part of the IP
address using a # character.	address using a # character.
More than one -S flag is allowed, with	More than one \fB--server\fP flag is allowed, with
repeated domain or ipaddr parts as required.	repeated domain or ipaddr parts as required.

More specific domains take precendence over less specific domains, so:	More specific domains take precedence over less specific domains, so:
.B --server=/google.com/1.2.3.4	.B --server=/google.com/1.2.3.4
.B --server=/www.google.com/2.3.4.5	.B --server=/www.google.com/2.3.4.5
will send queries for .google.com to 1.2.3.4, except www.google.com,	will send queries for google.com and gmail.google.com to 1.2.3.4, but www.google.com
which will go to 2.3.4.5	will go to 2.3.4.5

	Matching of domains is normally done on complete labels, so /google.com/ matches google.com and www.google.com
	but NOT supergoogle.com. This can be overridden with a * at the start of a pattern only: /*google.com/
	will match google.com and www.google.com AND supergoogle.com. The non-wildcard form has priority, so
	if /google.com/ and /*google.com/ are both specified then google.com and www.google.com will match /google.com/
	and /*google.com/ will only match supergoogle.com.

	For historical reasons, the pattern /.google.com/ is equivalent to /google.com/ if you wish to match any subdomain
	of google.com but NOT google.com itself, use /*.google.com/

The special server address '#' means, "use the standard servers", so	The special server address '#' means, "use the standard servers", so
.B --server=/google.com/1.2.3.4	.B --server=/google.com/1.2.3.4
.B --server=/www.google.com/#	.B --server=/www.google.com/#
will send queries for .google.com to 1.2.3.4, except www.google.com which will	will send queries for google.com and its subdomains to 1.2.3.4, except www.google.com (and its subdomains) which will
be forwarded as usual.	be forwarded as usual.

Also permitted is a -S	Also permitted is a -S
Line 402 flag which gives a domain but no IP address; this tell	Line 512 flag which gives a domain but no IP address; this tell
a domain is local and it may answer queries from /etc/hosts or DHCP	a domain is local and it may answer queries from /etc/hosts or DHCP
but should never forward queries on that domain to any upstream	but should never forward queries on that domain to any upstream
servers.	servers.
.B local	.B --local
is a synonym for	is a synonym for
.B server	.B --server
to make configuration files clearer in this case.	to make configuration files clearer in this case.

IPv6 addresses may include a %interface scope-id, eg	IPv6 addresses may include an %interface scope-id, eg
fe80::202:a412:4512:7bbf%eth0.	fe80::202:a412:4512:7bbf%eth0.

The optional string after the @ character tells	The optional string after the @ character tells dnsmasq how to set the source of
dnsmasq how to set the source of the queries to this	the queries to this nameserver. It can either be an ip-address, an interface
nameserver. It should be an ip-address, which should belong to the machine on which	name or both. The ip-address should belong to the machine on which dnsmasq is
dnsmasq is running otherwise this server line will be logged and then	running, otherwise this server line will be logged and then ignored. If an
ignored, or an interface name. If an interface name is given, then	interface name is given, then queries to the server will be forced via that
queries to the server will be forced via that interface; if an	interface; if an ip-address is given then the source address of the queries will
ip-address is given then the source address of the queries will be set	be set to that address; and if both are given then a combination of ip-address
to that address.	and interface name will be used to steer requests to the server.
The query-port flag is ignored for any servers which have a	The query-port flag is ignored for any servers which have a
source address specified but the port may be specified directly as	source address specified but the port may be specified directly as
part of the source address. Forcing queries to an interface is not	part of the source address. Forcing queries to an interface is not
implemented on all platforms supported by dnsmasq.	implemented on all platforms supported by dnsmasq.

	Upstream servers may be specified with a hostname rather than an IP address.
	In this case, dnsmasq will try to use the system resolver to get the IP address
	of a server during startup. If name resolution fails, starting dnsmasq fails, too.
	If the system's configuration is such that the system resolver sends DNS queries
	through the dnsmasq instance which is starting up then this will time-out and fail.
.TP	.TP
.B --rev-server=<ip-address>/<prefix-len>,<ipaddr>[#<port>][@<source-ip>\|<interface>[#<port>]]	.B --rev-server=<ip-address>[/<prefix-len>][,<server>][#<port>][@<interface>][@<source-ip>[#<port>]]
This is functionally the same as	This is functionally the same as
.B --server,	.B --server,
but provides some syntactic sugar to make specifying address-to-name queries easier. For example	but provides some syntactic sugar to make specifying address-to-name queries easier. For example
.B --rev-server=1.2.3.0/24,192.168.0.1	.B --rev-server=1.2.3.0/24,192.168.0.1
is exactly equivalent to	is exactly equivalent to
.B --server=/3.2.1.in-addr.arpa/192.168.0.1	.B --server=/3.2.1.in-addr.arpa/192.168.0.1
	Allowed prefix lengths are 1-32 (IPv4) and 1-128 (IPv6). If the prefix length is omitted, dnsmasq substitutes either 32 (IPv4) or 128 (IPv6).
.TP	.TP
.B \-A, --address=/<domain>/[domain/]<ipaddr>	.B \-A, --address=/<domain>[/<domain>...]/[<ipaddr>]
Specify an IP address to return for any host in the given domains.	Specify an IP address to return for any host in the given domains.
Queries in the domains are never forwarded and always replied to	A (or AAAA) queries in the domains are never forwarded and always replied to
with the specified IP address which may be IPv4 or IPv6. To give	with the specified IP address which may be IPv4 or IPv6. To give
both IPv4 and IPv6 addresses for a domain, use repeated -A flags.	multiple addresses or both IPv4 and IPv6 addresses for a domain, use repeated \fB--address\fP flags.
Note that /etc/hosts and DHCP leases override this for individual	Note that /etc/hosts and DHCP leases override this for individual
names. A common use of this is to redirect the entire doubleclick.net	names. A common use of this is to redirect the entire doubleclick.net
domain to some friendly local web server to avoid banner ads. The	domain to some friendly local web server to avoid banner ads. The
domain specification works in the same was as for --server, with the	domain specification works in the same way as for \fB--server\fP, with
additional facility that /#/ matches any domain. Thus	the additional facility that \fB/#/\fP matches any domain. Thus
--address=/#/1.2.3.4 will always return 1.2.3.4 for any query not	\fB--address=/#/1.2.3.4\fP will always return \fB1.2.3.4\fP for any
answered from /etc/hosts or DHCP and not sent to an upstream	query not answered from \fB/etc/hosts\fP or DHCP and not sent to an
nameserver by a more specific --server directive.	upstream nameserver by a more specific \fB--server\fP directive. As for
	\fB--server\fP, one or more domains with no address returns a
	no-such-domain answer, so \fB--address=/example.com/\fP is equivalent to
	\fB--server=/example.com/\fP and returns NXDOMAIN for example.com and
	all its subdomains. An address specified as '#' translates to the NULL
	address of 0.0.0.0 and its IPv6 equivalent of :: so
	\fB--address=/example.com/#\fP will return NULL addresses for example.com and
	its subdomains. This is partly syntactic sugar for \fB--address=/example.com/0.0.0.0\fP
	and \fB--address=/example.com/::\fP but is also more efficient than including both
	as separate configuration lines. Note that NULL addresses normally work in the same way as localhost, so beware that clients looking up these names are likely to end up talking to themselves.

	Note that the behaviour for queries which don't match the specified address literal changed in version 2.86.
	Previous versions, configured with (eg) --address=/example.com/1.2.3.4 and then queried for a RR type other than
	A would return a NoData answer. From 2.86, the query is sent upstream. To restore the pre-2.86 behaviour,
	use the configuration --address=/example.com/1.2.3.4 --local=/example.com/
.TP	.TP
.B --ipset=/<domain>/[domain/]<ipset>[,<ipset>]	.B --ipset=/<domain>[/<domain>...]/<ipset>[,<ipset>...]
Places the resolved IP addresses of queries for the specified domains	Places the resolved IP addresses of queries for one or more domains in
in the specified netfilter ip sets. Domains and subdomains are matched	the specified Netfilter IP set. If multiple setnames are given, then the
in the same way as --address. These ip sets must already exist. See	addresses are placed in each of them, subject to the limitations of an
ipset(8) for more details.	IP set (IPv4 addresses cannot be stored in an IPv6 IP set and vice
	versa). Domains and subdomains are matched in the same way as
	\fB--address\fP.
	These IP sets must already exist. See
	.BR ipset (8)
	for more details.
.TP	.TP
	.B --nftset=/<domain>[/<domain>...]/[(6\|4)#[<family>#]<table>#<set>[,[(6\|4)#[<family>#]<table>#<set>]...]
	Similar to the \fB--ipset\fP option, but accepts one or more nftables
	sets to add IP addresses into.
	These sets must already exist. See
	.BR nft (8)
	for more details. The family, table and set are passed directly to the nft. If the spec starts with 4# or 6# then
	only A or AAAA records respectively are added to the set. Since an nftset can hold only IPv4 or IPv6 addresses, this
	avoids errors being logged for addresses of the wrong type.
	.TP
	.B --connmark-allowlist-enable[=<mask>]
	Enables filtering of incoming DNS queries with associated Linux connection track marks
	according to individual allowlists configured via a series of \fB--connmark-allowlist\fP
	options. Disallowed queries are not forwarded; they are rejected with a REFUSED error code.
	DNS queries are only allowed if they do not have an associated Linux connection
	track mark, or if the queried domains match the configured DNS patterns for the
	associated Linux connection track mark. If no allowlist is configured for a
	Linux connection track mark, all DNS queries associated with that mark are rejected.
	If a mask is specified, Linux connection track marks are first bitwise ANDed
	with the given mask before being processed.
	.TP
	.B --connmark-allowlist=<connmark>[/<mask>][,<pattern>[/<pattern>...]]
	Configures the DNS patterns that are allowed in DNS queries associated with
	the given Linux connection track mark.
	If a mask is specified, Linux connection track marks are first bitwise ANDed
	with the given mask before they are compared to the given connection track mark.
	Patterns follow the syntax of DNS names, but additionally allow the wildcard
	character "*" to be used up to twice per label to match 0 or more characters
	within that label. Note that the wildcard never matches a dot (e.g., "*.example.com"
	matches "api.example.com" but not "api.us.example.com"). Patterns must be
	fully qualified, i.e., consist of at least two labels. The final label must not be
	fully numeric, and must not be the "local" pseudo-TLD. A pattern must end with at least
	two literal (non-wildcard) labels.
	Instead of a pattern, "*" can be specified to disable allowlist filtering
	for a given Linux connection track mark entirely.
	.TP
.B \-m, --mx-host=<mx name>[[,<hostname>],<preference>]	.B \-m, --mx-host=<mx name>[[,<hostname>],<preference>]
Return an MX record named <mx name> pointing to the given hostname (if	Return an MX record named <mx name> pointing to the given hostname (if
given), or	given), or
the host specified in the --mx-target switch	the host specified in the \fB--mx-target\fP switch
or, if that switch is not given, the host on which dnsmasq	or, if that switch is not given, the host on which dnsmasq
is running. The default is useful for directing mail from systems on a LAN	is running. The default is useful for directing mail from systems on a LAN
to a central server. The preference value is optional, and defaults to	to a central server. The preference value is optional, and defaults to
Line 462 to a central server. The preference value is optional,	Line 633 to a central server. The preference value is optional,
.TP	.TP
.B \-t, --mx-target=<hostname>	.B \-t, --mx-target=<hostname>
Specify the default target for the MX record returned by dnsmasq. See	Specify the default target for the MX record returned by dnsmasq. See
--mx-host. If --mx-target is given, but not --mx-host, then dnsmasq	\fB--mx-host\fP. If \fB--mx-target\fP is given, but not \fB--mx-host\fP, then dnsmasq
returns a MX record containing the MX target for MX queries on the	returns a MX record containing the MX target for MX queries on the
hostname of the machine on which dnsmasq is running.	hostname of the machine on which dnsmasq is running.
.TP	.TP
Line 471 Return an MX record pointing to itself for each local	Line 642 Return an MX record pointing to itself for each local
machine. Local machines are those in /etc/hosts or with DHCP leases.	machine. Local machines are those in /etc/hosts or with DHCP leases.
.TP	.TP
.B \-L, --localmx	.B \-L, --localmx
Return an MX record pointing to the host given by mx-target (or the	Return an MX record pointing to the host given by \fB--mx-target\fP (or the
machine on which dnsmasq is running) for each	machine on which dnsmasq is running) for each
local machine. Local machines are those in /etc/hosts or with DHCP	local machine. Local machines are those in /etc/hosts or with DHCP
leases.	leases.
Line 487 zone files: the port, weight and priority numbers are	Line 658 zone files: the port, weight and priority numbers are
order. More than one SRV record for a given service/domain is allowed,	order. More than one SRV record for a given service/domain is allowed,
all that match are returned.	all that match are returned.
.TP	.TP
.B --host-record=<name>[,<name>....][<IPv4-address>],[<IPv6-address>]	.B --host-record=<name>[,<name>....],[<IPv4-address>],[<IPv6-address>][,<TTL>]
Add A, AAAA and PTR records to the DNS. This adds one or more names to	Add A, AAAA and PTR records to the DNS. This adds one or more names to
the DNS with associated IPv4 (A) and IPv6 (AAAA) records. A name may	the DNS with associated IPv4 (A) and IPv6 (AAAA) records. A name may
appear in more than one	appear in more than one
.B host-record	.B --host-record
and therefore be assigned more than one address. Only the first	and therefore be assigned more than one address. Only the first
address creates a PTR record linking the address to the name. This is	address creates a PTR record linking the address to the name. This is
the same rule as is used reading hosts-files.	the same rule as is used reading hosts-files.
.B host-record	.B --host-record
options are considered to be read before host-files, so a name	options are considered to be read before host-files, so a name
appearing there inhibits PTR-record creation if it appears in	appearing there inhibits PTR-record creation if it appears in
hosts-file also. Unlike hosts-files, names are not expanded, even when	hosts-file also. Unlike hosts-files, names are not expanded, even when
.B expand-hosts	.B --expand-hosts
is in effect. Short and long names may appear in the same	is in effect. Short and long names may appear in the same
.B host-record,	.B --host-record,
eg.	eg.
.B --host-record=laptop,laptop.thekelleys.org,192.168.0.1,1234::100	.B --host-record=laptop,laptop.thekelleys.org,192.168.0.1,1234::100

	If the time-to-live is given, it overrides the default, which is zero
	or the value of \fB--local-ttl\fP. The value is a positive integer and gives
	the time-to-live in seconds.
.TP	.TP
	.B --dynamic-host=<name>,[IPv4-address],[IPv6-address],<interface>
	Add A, AAAA and PTR records to the DNS in the same subnet as the specified interface. The address is derived from the network part of each address associated with the interface, and the host part from the specified address. For example
	.B --dynamic-host=example.com,0.0.0.8,eth0
	will, when eth0 has the address 192.168.78.x and netmask 255.255.255.0 give the
	name example.com an A record for 192.168.78.8. The same principle applies to IPv6 addresses. Note that if an interface has more than one address, more than one A or AAAA record will be created. The TTL of the records is always zero, and any changes to interface addresses will be immediately reflected in them.
	.TP
.B \-Y, --txt-record=<name>[[,<text>],<text>]	.B \-Y, --txt-record=<name>[[,<text>],<text>]
Return a TXT DNS record. The value of TXT record is a set of strings,	Return a TXT DNS record. The value of TXT record is a set of strings,
so any number may be included, delimited by commas; use quotes to put	so any number may be included, delimited by commas; use quotes to put
Line 517 Return a PTR DNS record.	Line 698 Return a PTR DNS record.
.B --naptr-record=<name>,<order>,<preference>,<flags>,<service>,<regexp>[,<replacement>]	.B --naptr-record=<name>,<order>,<preference>,<flags>,<service>,<regexp>[,<replacement>]
Return an NAPTR DNS record, as specified in RFC3403.	Return an NAPTR DNS record, as specified in RFC3403.
.TP	.TP
.B --cname=<cname>,<target>	.B --caa-record=<name>,<flags>,<tag>,<value>
	Return a CAA DNS record, as specified in RFC6844.
	.TP
	.B --cname=<cname>,[<cname>,]<target>[,<TTL>]
Return a CNAME record which indicates that <cname> is really	Return a CNAME record which indicates that <cname> is really
<target>. There are significant limitations on the target; it must be a	<target>. There is a significant limitation on the target; it must be a
DNS name which is known to dnsmasq from /etc/hosts (or additional	DNS record which is known to dnsmasq and NOT a DNS record which comes from
hosts files), from DHCP, from --interface-name or from another	an upstream server. The cname must be unique, but it
.B --cname.	is permissible to have more than one cname pointing to the same target. Indeed
If the target does not satisfy this	it's possible to declare multiple cnames to a target in a single line, like so:
criteria, the whole cname is ignored. The cname must be unique, but it	.B --cname=cname1,cname2,target
is permissable to have more than one cname pointing to the same target.
	If the time-to-live is given, it overrides the default, which is zero
	or the value of \fB--local-ttl\fP. The value is a positive integer and gives
	the time-to-live in seconds.
.TP	.TP
.B --dns-rr=<name>,<RR-number>,[<hex data>]	.B --dns-rr=<name>,<RR-number>,[<hex data>]
Return an arbitrary DNS Resource Record. The number is the type of the	Return an arbitrary DNS Resource Record. The number is the type of the
Line 534 given by the hex data, which may be of the form 01:23:	Line 721 given by the hex data, which may be of the form 01:23:
012345 or any mixture of these.	012345 or any mixture of these.
.TP	.TP
.B --interface-name=<name>,<interface>[/4\|/6]	.B --interface-name=<name>,<interface>[/4\|/6]
Return a DNS record associating the name with the primary address on	Return DNS records associating the name with the address(es) of
the given interface. This flag specifies an A or AAAA record for the given	the given interface. This flag specifies an A or AAAA record for the given
name in the same way as an /etc/hosts line, except that the address is	name in the same way as an /etc/hosts line, except that the address is
not constant, but taken from the given interface. The interface may be	not constant, but taken from the given interface. The interface may be
Line 544 down, not configured or non-existent, an empty record	Line 731 down, not configured or non-existent, an empty record
matching PTR record is also created, mapping the interface address to	matching PTR record is also created, mapping the interface address to
the name. More than one name may be associated with an interface	the name. More than one name may be associated with an interface
address by repeating the flag; in that case the first instance is used	address by repeating the flag; in that case the first instance is used
for the reverse address-to-name mapping.	for the reverse address-to-name mapping. Note that a name used in
	\fB--interface-name\fP may not appear in /etc/hosts.
.TP	.TP
.B --synth-domain=<domain>,<address range>[,<prefix>]	.B --synth-domain=<domain>,<address range>[,<prefix>[*]]
Create artificial A/AAAA and PTR records for an address range. The	Create artificial A/AAAA and PTR records for an address range. The
records use the address, with periods (or colons for IPv6) replaced	records either seqential numbers or the address, with periods (or colons for IPv6) replaced with dashes.
with dashes.

An example should make this clearer.	An examples should make this clearer. First sequential numbers.
.B --synth-domain=thekelleys.org.uk,192.168.0.0/24,internal-	.B --synth-domain=thekelleys.org.uk,192.168.0.50,192.168.0.70,internal-*
	results in the name internal-0.thekelleys.org.uk. returning 192.168.0.50, internal-1.thekelleys.org.uk returning 192.168.0.51 and so on. (note the *) The same principle applies to IPv6 addresses (where the numbers may be very large). Reverse lookups from address to name behave as expected.

	Second,
	.B --synth-domain=thekelleys.org.uk,192.168.0.0/24,internal- (no *)
will result in a query for internal-192-168-0-56.thekelleys.org.uk returning	will result in a query for internal-192-168-0-56.thekelleys.org.uk returning
192.168.0.56 and a reverse query vice versa. The same applies to IPv6,	192.168.0.56 and a reverse query vice versa. The same applies to IPv6,
but IPv6 addresses may start with '::'	but IPv6 addresses may start with '::'
but DNS labels may not start with '-' so in this case if no prefix is	but DNS labels may not start with '-' so in this case if no prefix is
configured a zero is added in front of the label. ::1 becomes 0--1.	configured a zero is added in front of the label. ::1 becomes 0--1.

	V4 mapped IPv6 addresses, which have a representation like ::ffff:1.2.3.4 are handled specially, and become like 0--ffff-1-2-3-4

The address range can be of the form	The address range can be of the form
<ip address>,<ip address> or <ip address>/<netmask>	<start address>,<end address> or <ip address>/<prefix-length> in both forms of the option. For IPv6 the start and end addresses
	must fall in the same /64 network, or prefix-length must be greater than or equal to 64 except that shorter prefix lengths than 64 are allowed only if non-sequential names are in use.
.TP	.TP
.B --add-mac	.B --dumpfile=<path/to/file>
	Specify the location of a pcap-format file which dnsmasq uses to dump copies of network packets for debugging purposes. If the file exists when dnsmasq starts, it is not deleted; new packets are added to the end.
	.TP
	.B --dumpmask=<mask>
	Specify which types of packets should be added to the dumpfile. The argument should be the OR of the bitmasks for each type of packet to be dumped: it can be specified in hex by preceding the number with 0x in the normal way. Each time a packet is written to the dumpfile, dnsmasq logs the packet sequence and the mask
	representing its type. The current types are: 0x0001 - DNS queries from clients, 0x0002 DNS replies to clients, 0x0004 - DNS queries to upstream, 0x0008 - DNS replies from upstream, 0x0010 - queries send upstream for DNSSEC validation, 0x0020 - replies to queries for DNSSEC validation, 0x0040 - replies to client queries which fail DNSSEC validation, 0x0080 replies to queries for DNSSEC validation which fail validation, 0x1000 - DHCPv4, 0x2000 - DHCPv6, 0x4000 - Router advertisement, 0x8000 - TFTP.
	.TP
	.B --add-mac[=base64\|text]
Add the MAC address of the requestor to DNS queries which are	Add the MAC address of the requestor to DNS queries which are
forwarded upstream. This may be used to DNS filtering by the upstream	forwarded upstream. This may be used to DNS filtering by the upstream
server. The MAC address can only be added if the requestor is on the same	server. The MAC address can only be added if the requestor is on the same
Line 570 subnet as the dnsmasq server. Note that the mechanism	Line 771 subnet as the dnsmasq server. Note that the mechanism
is not yet standardised, so this should be considered	is not yet standardised, so this should be considered
experimental. Also note that exposing MAC addresses in this way may	experimental. Also note that exposing MAC addresses in this way may
have security and privacy implications. The warning about caching	have security and privacy implications. The warning about caching
given for --add-subnet applies to --add-mac too.	given for \fB--add-subnet\fP applies to \fB--add-mac\fP too. An alternative encoding of the
	MAC, as base64, is enabled by adding the "base64" parameter and a human-readable encoding of hex-and-colons is enabled by added the "text" parameter.
	.TP
	.B --strip-mac
	Remove any MAC address information already in downstream queries before forwarding upstream.
	.TP
	.B --add-cpe-id=<string>
	Add an arbitrary identifying string to DNS queries which are
	forwarded upstream.
.TP	.TP
.B --add-subnet[[=<IPv4 prefix length>],<IPv6 prefix length>]	.B --add-subnet[[=[<IPv4 address>/]<IPv4 prefix length>][,[<IPv6 address>/]<IPv6 prefix length>]]
Add the subnet address of the requestor to the DNS queries which are	Add a subnet address to the DNS queries which are forwarded
forwarded upstream. The amount of the address forwarded depends on the	upstream. If an address is specified in the flag, it will be used,
prefix length parameter: 32 (128 for IPv6) forwards the whole address,	otherwise, the address of the requestor will be used. The amount of
zero forwards none of it but still marks the request so that no	the address forwarded depends on the prefix length parameter: 32 (128
upstream nameserver will add client address information either. The	for IPv6) forwards the whole address, zero forwards none of it but
default is zero for both IPv4 and IPv6. Note that upstream nameservers	still marks the request so that no upstream nameserver will add client
may be configured to return different results based on this	address information either. The default is zero for both IPv4 and
information, but the dnsmasq cache does not take account. If a dnsmasq	IPv6. Note that upstream nameservers may be configured to return
instance is configured such that different results may be encountered,	different results based on this information, but the dnsmasq cache
caching should be disabled.	does not take account. Caching is therefore disabled for such replies,
	unless the subnet address being added is constant.

	For example,
	.B --add-subnet=24,96
	will add the /24 and /96 subnets of the requestor for IPv4 and IPv6 requestors, respectively.
	.B --add-subnet=1.2.3.4/24
	will add 1.2.3.0/24 for IPv4 requestors and ::/0 for IPv6 requestors.
	.B --add-subnet=1.2.3.4/24,1.2.3.4/24
	will add 1.2.3.0/24 for both IPv4 and IPv6 requestors.
.TP	.TP
	.B --strip-subnet
	Remove any subnet address already present in a downstream query before forwarding it upstream. If --add-subnet is set this also
	ensures that any downstream-provided subnet is replaced by the one added by dnsmasq. Otherwise, dnsmasq will NOT replace an
	existing subnet in the query.
	.TP
	.B --umbrella[=[deviceid:<deviceid>][,orgid:<orgid>][,assetid:<id>]]
	Embeds the requestor's IP address in DNS queries forwarded upstream.
	If device id or, asset id or organization id are specified, the information is
	included in the forwarded queries and may be able to be used in
	filtering policies and reporting. The order of the id
	attributes is irrelevant, but they must be separated by a comma. Deviceid is
	a sixteen digit hexadecimal number, org and asset ids are decimal numbers.
	.TP
.B \-c, --cache-size=<cachesize>	.B \-c, --cache-size=<cachesize>
Set the size of dnsmasq's cache. The default is 150 names. Setting the cache size to zero disables caching.	Set the size of dnsmasq's cache. The default is 150 names. Setting the cache size to zero disables caching. Note: huge cache size impacts performance.
.TP	.TP
.B \-N, --no-negcache	.B \-N, --no-negcache
Disable negative caching. Negative caching allows dnsmasq to remember	Disable negative caching. Negative caching allows dnsmasq to remember
"no such domain" answers from upstream nameservers and answer	"no such domain" answers from upstream nameservers and answer
identical queries without forwarding them again.	identical queries without forwarding them again.
.TP	.TP
	.B --no-round-robin
	Dnsmasq normally permutes the order of A or AAAA records for the same
	name on successive queries, for load-balancing. This turns off that
	behaviour, so that the records are always returned in the order
	that they are received from upstream.
	.TP
	.B --use-stale-cache[=<max TTL excess in s>]
	When set, if a DNS name exists in the cache, but its time-to-live has expired, dnsmasq will return the data anyway. (It attempts to refresh the
	data with an upstream query after returning the stale data.) This can improve speed and reliability. It comes at the expense
	of sometimes returning out-of-date data and less efficient cache utilisation, since old data cannot be flushed when its TTL expires, so the cache becomes
	mostly least-recently-used. To mitigate issues caused by massively outdated DNS replies, the maximum overaging of cached records can be specified in seconds
	(defaulting to not serve anything older than one day). Setting the TTL excess time to zero will serve stale cache data regardless how long it has expired.
	.TP
.B \-0, --dns-forward-max=<queries>	.B \-0, --dns-forward-max=<queries>
Set the maximum number of concurrent DNS queries. The default value is	Set the maximum number of concurrent DNS queries. The default value is
150, which should be fine for most setups. The only known situation	150, which should be fine for most setups. The only known situation
where this needs to be increased is when using web-server log file	where this needs to be increased is when using web-server log file
resolvers, which can generate large numbers of concurrent queries.	resolvers, which can generate large numbers of concurrent queries. This
	parameter actually controls the number of concurrent queries per server group, where a server group is the set of server(s) associated with a single domain. So if a domain has it's own server via --server=/example.com/1.2.3.4 and 1.2.3.4 is not responding, but queries for *.example.com cannot go elsewhere, then other queries will not be affected. On configurations with many such server groups and tight resources, this value may need to be reduced.
.TP	.TP
.B --dnssec	.B --dnssec
Validate DNS replies and cache DNSSEC data. When forwarding DNS queries, dnsmasq requests the	Validate DNS replies and cache DNSSEC data. When forwarding DNS queries, dnsmasq requests the
Line 612 permitted to reduce the cache size below the default w	Line 857 permitted to reduce the cache size below the default w
enabled. The nameservers upstream of dnsmasq must be DNSSEC-capable,	enabled. The nameservers upstream of dnsmasq must be DNSSEC-capable,
ie capable of returning DNSSEC records with data. If they are not,	ie capable of returning DNSSEC records with data. If they are not,
then dnsmasq will not be able to determine the trusted status of	then dnsmasq will not be able to determine the trusted status of
answers. In the default mode, this menas that all replies will be	answers and this means that DNS service will be entirely broken.
marked as untrusted. If
.B --dnssec-check-unsigned
is set and the upstream servers don't support DNSSEC, then DNS service will be entirely broken.
.TP	.TP
.B --trust-anchor=[<class>],<domain>,<key-tag>,<algorithm>,<digest-type>,<digest>	.B --trust-anchor=[<class>],<domain>,<key-tag>,<algorithm>,<digest-type>,<digest>
Provide DS records to act a trust anchors for DNSSEC	Provide DS records to act a trust anchors for DNSSEC
validation. Typically these will be the DS record(s) for Zone Signing	validation. Typically these will be the DS record(s) for Key Signing
key(s) of the root zone,	key(s) (KSK) of the root zone,
but trust anchors for limited domains are also possible. The current	but trust anchors for limited domains are also possible. The current
root-zone trust anchors may be donwloaded from https://data.iana.org/root-anchors/root-anchors.xml	root-zone trust anchors may be downloaded from https://data.iana.org/root-anchors/root-anchors.xml
.TP	.TP
.B --dnssec-check-unsigned	.B --dnssec-check-unsigned[=no]
As a default, dnsmasq does not check that unsigned DNS replies are	As a default, dnsmasq checks that unsigned DNS replies are
legitimate: they are assumed to be valid and passed on (without the	legitimate: this entails possible extra queries even for the majority of DNS
	zones which are not, at the moment, signed. If
	.B --dnssec-check-unsigned=no
	appears in the configuration, then such replies they are assumed to be valid and passed on (without the
"authentic data" bit set, of course). This does not protect against an	"authentic data" bit set, of course). This does not protect against an
attacker forging unsigned replies for signed DNS zones, but it is	attacker forging unsigned replies for signed DNS zones, but it is
fast. If this flag is set, dnsmasq will check the zones of unsigned	fast.
replies, to ensure that unsigned replies are allowed in those
zones. The cost of this is more upstream queries and slower	Versions of dnsmasq prior to 2.80 defaulted to not checking unsigned replies, and used
performance. See also the warning about upstream servers in the	.B --dnssec-check-unsigned
section on	to switch this on. Such configurations will continue to work as before, but those which used the default of no checking will need to be altered to explicitly select no checking. The new default is because switching off checking for unsigned replies is inherently dangerous. Not only does it open the possiblity of forged replies, but it allows everything to appear to be working even when the upstream namesevers do not support DNSSEC, and in this case no DNSSEC validation at all is occurring.
.B --dnssec
.TP	.TP
.B --dnssec-no-timecheck	.B --dnssec-no-timecheck
DNSSEC signatures are only valid for specified time windows, and should be rejected outside those windows. This generates an	DNSSEC signatures are only valid for specified time windows, and should be rejected outside those windows. This generates an
interesting chicken-and-egg problem for machines which don't have a hardware real time clock. For these machines to determine the correct	interesting chicken-and-egg problem for machines which don't have a hardware real time clock. For these machines to determine the correct
time typically requires use of NTP and therefore DNS, but validating DNS requires that the correct time is already known. Setting this flag	time typically requires use of NTP and therefore DNS, but validating DNS requires that the correct time is already known. Setting this flag
removes the time-window checks (but not other DNSSEC validation.) only until the dnsmasq process receives SIGHUP. The intention is	removes the time-window checks (but not other DNSSEC validation.) only until the dnsmasq process receives SIGINT. The intention is
that dnsmasq should be started with this flag when the platform determines that reliable time is not currently available. As soon as	that dnsmasq should be started with this flag when the platform determines that reliable time is not currently available. As soon as
reliable time is established, a SIGHUP should be sent to dnsmasq, which enables time checking, and purges the cache of DNS records	reliable time is established, a SIGINT should be sent to dnsmasq, which enables time checking, and purges the cache of DNS records
which have not been throughly checked.	which have not been thoroughly checked.

	Earlier versions of dnsmasq overloaded SIGHUP (which re-reads much configuration) to also enable time validation.

	If dnsmasq is run in debug mode (\fB--no-daemon\fP flag) then SIGINT retains its usual meaning of terminating the dnsmasq process.
.TP	.TP
	.B --dnssec-timestamp=<path>
	Enables an alternative way of checking the validity of the system time for DNSSEC (see \fB--dnssec-no-timecheck\fP). In this case, the
	system time is considered to be valid once it becomes later than the timestamp on the specified file. The file is created and
	its timestamp set automatically by dnsmasq. The file must be stored on a persistent filesystem, so that it and its mtime are carried
	over system restarts. The timestamp file is created after dnsmasq has dropped root, so it must be in a location writable by the
	unprivileged user that dnsmasq runs as.
	.TP
.B --proxy-dnssec	.B --proxy-dnssec
Copy the DNSSEC Authenticated Data bit from upstream servers to downstream clients and cache it. This is an	Copy the DNSSEC Authenticated Data bit from upstream servers to downstream clients. This is an
alternative to having dnsmasq validate DNSSEC, but it depends on the security of the network between	alternative to having dnsmasq validate DNSSEC, but it depends on the security of the network between
dnsmasq and the upstream servers, and the trustworthiness of the upstream servers.	dnsmasq and the upstream servers, and the trustworthiness of the upstream servers. Note that caching the
	Authenticated Data bit correctly in all cases is not technically possible. If the AD bit is to be relied upon
	when using this option, then the cache should be disabled using --cache-size=0. In most cases, enabling DNSSEC validation
	within dnsmasq is a better option. See --dnssec for details.
.TP	.TP
.B --dnssec-debug	.B --dnssec-debug
Set debugging mode for the DNSSEC validation, set the Checking Disabled bit on upstream queries,	Set debugging mode for the DNSSEC validation, set the Checking Disabled bit on upstream queries,
Line 657 a return code of SERVFAIL. Note that	Line 915 a return code of SERVFAIL. Note that
setting this may affect DNS behaviour in bad ways, it is not an	setting this may affect DNS behaviour in bad ways, it is not an
extra-logging flag and should not be set in production.	extra-logging flag and should not be set in production.
.TP	.TP
.B --auth-zone=<domain>[,<subnet>[/<prefix length>][,<subnet>[/<prefix length>].....]]	.B --auth-zone=<domain>[,<subnet>[/<prefix length>][,<subnet>[/<prefix length>].....][,exclude:<subnet>[/<prefix length>]].....]
Define a DNS zone for which dnsmasq acts as authoritative server. Locally defined DNS records which are in the domain	Define a DNS zone for which dnsmasq acts as authoritative server. Locally defined DNS records which are in the domain
will be served. If subnet(s) are given, A and AAAA records must be in one of the	will be served. If subnet(s) are given, A and AAAA records must be in one of the
specified subnets.	specified subnets.
Line 672 interface addresses may be confined to only IPv6 addre	Line 930 interface addresses may be confined to only IPv6 addre
an interface has dynamically determined global IPv6 addresses which should	an interface has dynamically determined global IPv6 addresses which should
appear in the zone, but RFC1918 IPv4 addresses which should not.	appear in the zone, but RFC1918 IPv4 addresses which should not.
Interface-name and address-literal subnet specifications may be used	Interface-name and address-literal subnet specifications may be used
freely in the same --auth-zone declaration.	freely in the same \fB--auth-zone\fP declaration.

	It's possible to exclude certain IP addresses from responses. It can be
	used, to make sure that answers contain only global routeable IP
	addresses (by excluding loopback, RFC1918 and ULA addresses).

The subnet(s) are also used to define in-addr.arpa and	The subnet(s) are also used to define in-addr.arpa and
ip6.arpa domains which are served for reverse-DNS queries. If not	ip6.arpa domains which are served for reverse-DNS queries. If not
specified, the prefix length defaults to 24 for IPv4 and 64 for IPv6.	specified, the prefix length defaults to 24 for IPv4 and 64 for IPv6.
Line 695 authoritative zones as dnsmasq.	Line 957 authoritative zones as dnsmasq.
.B --auth-peer=<ip-address>[,<ip-address>[,<ip-address>...]]	.B --auth-peer=<ip-address>[,<ip-address>[,<ip-address>...]]
Specify the addresses of secondary servers which are allowed to	Specify the addresses of secondary servers which are allowed to
initiate zone transfer (AXFR) requests for zones for which dnsmasq is	initiate zone transfer (AXFR) requests for zones for which dnsmasq is
authoritative. If this option is not given, then AXFR requests will be	authoritative. If this option is not given but --auth-sec-servers is,
accepted from any secondary.	then AXFR requests will be
	accepted from any secondary. Specifying
	.B --auth-peer
	without
	.B --auth-sec-servers
	enables zone transfer but does not advertise the secondary in NS records returned by dnsmasq.
.TP	.TP
.B --conntrack	.B --conntrack
Read the Linux connection track mark associated with incoming DNS	Read the Linux connection track mark associated with incoming DNS
Line 706 associated with the queries which cause it, useful for	Line 973 associated with the queries which cause it, useful for
accounting and firewalling. Dnsmasq must have conntrack support	accounting and firewalling. Dnsmasq must have conntrack support
compiled in and the kernel must have conntrack support	compiled in and the kernel must have conntrack support
included and configured. This option cannot be combined with	included and configured. This option cannot be combined with
--query-port.	.B --query-port.
.TP	.TP
.B \-F, --dhcp-range=[tag:<tag>[,tag:<tag>],][set:<tag>,]<start-addr>[,<end-addr>][,<mode>][,<netmask>[,<broadcast>]][,<lease time>]	.B \-F, --dhcp-range=[tag:<tag>[,tag:<tag>],][set:<tag>,]<start-addr>[,<end-addr>\|<mode>[,<netmask>[,<broadcast>]]][,<lease time>]
.TP	.TP
.B \-F, --dhcp-range=[tag:<tag>[,tag:<tag>],][set:<tag>,]<start-IPv6addr>[,<end-IPv6addr>\|constructor:<interface>][,<mode>][,<prefix-len>][,<lease time>]	.B \-F, --dhcp-range=[tag:<tag>[,tag:<tag>],][set:<tag>,]<start-IPv6addr>[,<end-IPv6addr>\|constructor:<interface>][,<mode>][,<prefix-len>][,<lease time>]

Enable the DHCP server. Addresses will be given out from the range	Enable the DHCP server. Addresses will be given out from the range
<start-addr> to <end-addr> and from statically defined addresses given	<start-addr> to <end-addr> and from statically defined addresses given
in	in
.B dhcp-host	.B --dhcp-host
options. If the lease time is given, then leases	options. If the lease time is given, then leases
will be given for that length of time. The lease time is in seconds,	will be given for that length of time. The lease time is in seconds,
or minutes (eg 45m) or hours (eg 1h) or "infinite". If not given,	or minutes (eg 45m) or hours (eg 1h) or days (2d) or weeks (1w) or "infinite". If not given,
the default lease time is one hour. The	the default lease time is one hour for IPv4 and one day for IPv6. The
minimum lease time is two minutes. For IPv6 ranges, the lease time	minimum lease time is two minutes. For IPv6 ranges, the lease time
maybe "deprecated"; this sets the preferred lifetime sent in a DHCP	maybe "deprecated"; this sets the preferred lifetime sent in a DHCP
lease or router advertisement to zero, which causes clients to use	lease or router advertisement to zero, which causes clients to use
Line 734 agent, dnsmasq cannot determine the netmask itself, so	Line 1001 agent, dnsmasq cannot determine the netmask itself, so
specified, otherwise dnsmasq will have to guess, based on the class (A, B or	specified, otherwise dnsmasq will have to guess, based on the class (A, B or
C) of the network address. The broadcast address is	C) of the network address. The broadcast address is
always optional. It is always	always optional. It is always
allowed to have more than one dhcp-range in a single subnet.	allowed to have more than one \fB--dhcp-range\fP in a single subnet.

For IPv6, the parameters are slightly different: instead of netmask	For IPv6, the parameters are slightly different: instead of netmask
and broadcast address, there is an optional prefix length which must	and broadcast address, there is an optional prefix length which must
be equal to or larger then the prefix length on the local interface. If not	be equal to or larger then the prefix length on the local interface. If not
given, this defaults to 64. Unlike the IPv4 case, the prefix length is not	given, this defaults to 64. Unlike the IPv4 case, the prefix length is not
automatically derived from the interface configuration. The mimimum	automatically derived from the interface configuration. The minimum
size of the prefix length is 64.	size of the prefix length is 64.

IPv6 (only) supports another type of range. In this, the start address and optional end address contain only the network part (ie ::1) and they are followed by	IPv6 (only) supports another type of range. In this, the start address and optional end address contain only the network part (ie ::1) and they are followed by
Line 758 then deleted. The interface name may have a final "*"	Line 1025 then deleted. The interface name may have a final "*"
that just any address on eth0 will not do: it must not be an	that just any address on eth0 will not do: it must not be an
autoconfigured or privacy address, or be deprecated.	autoconfigured or privacy address, or be deprecated.

If a dhcp-range is only being used for stateless DHCP and/or SLAAC,	If a \fB--dhcp-range\fP is only being used for stateless DHCP and/or SLAAC,
then the address can be simply ::	then the address can be simply ::

.B --dhcp-range=::,constructor:eth0	.B --dhcp-range=::,constructor:eth0
Line 767 then the address can be simply ::	Line 1034 then the address can be simply ::
The optional	The optional
.B set:<tag>	.B set:<tag>
sets an alphanumeric label which marks this network so that	sets an alphanumeric label which marks this network so that
dhcp options may be specified on a per-network basis.	DHCP options may be specified on a per-network basis.
When it is prefixed with 'tag:' instead, then its meaning changes from setting	When it is prefixed with 'tag:' instead, then its meaning changes from setting
a tag to matching it. Only one tag may be set, but more than one tag	a tag to matching it. Only one tag may be set, but more than one tag
may be matched.	may be matched.
Line 777 The optional <mode> keyword may be	Line 1044 The optional <mode> keyword may be
which tells dnsmasq to enable DHCP for the network specified, but not	which tells dnsmasq to enable DHCP for the network specified, but not
to dynamically allocate IP addresses: only hosts which have static	to dynamically allocate IP addresses: only hosts which have static
addresses given via	addresses given via
.B dhcp-host	.B --dhcp-host
or from /etc/ethers will be served. A static-only subnet with address	or from /etc/ethers will be served. A static-only subnet with address
all zeros may be used as a "catch-all" address to enable replies to all	all zeros may be used as a "catch-all" address to enable replies to all
Information-request packets on a subnet which is provided with	Information-request packets on a subnet which is provided with
Line 788 For IPv4, the <mode> may be	Line 1055 For IPv4, the <mode> may be
.B proxy	.B proxy
in which case dnsmasq will provide proxy-DHCP on the specified	in which case dnsmasq will provide proxy-DHCP on the specified
subnet. (See	subnet. (See
.B pxe-prompt	.B --pxe-prompt
and	and
.B pxe-service	.B --pxe-service
for details.)	for details.)

For IPv6, the mode may be some combination of	For IPv6, the mode may be some combination of
.B ra-only, slaac, ra-names, ra-stateless.	.B ra-only, slaac, ra-names, ra-stateless, ra-advrouter, off-link.

.B ra-only	.B ra-only
tells dnsmasq to offer Router Advertisement only on this subnet,	tells dnsmasq to offer Router Advertisement only on this subnet,
Line 829 can be combined with	Line 1096 can be combined with
and	and
.B slaac.	.B slaac.

	.B ra-advrouter
	enables a mode where router address(es) rather than prefix(es) are included in the advertisements.
	This is described in RFC-3775 section 7.2 and is used in mobile IPv6. In this mode the interval option
	is also included, as described in RFC-3775 section 7.3.

	.B off-link
	tells dnsmasq to advertise the prefix without the on-link (aka L) bit set.

.TP	.TP
.B \-G, --dhcp-host=[<hwaddr>][,id:<client_id>\|*][,set:<tag>][,<ipaddr>][,<hostname>][,<lease_time>][,ignore]	.B \-G, --dhcp-host=[<hwaddr>][,id:<client_id>\|*][,set:<tag>][,tag:<tag>][,<ipaddr>][,<hostname>][,<lease_time>][,ignore]
Specify per host parameters for the DHCP server. This allows a machine	Specify per host parameters for the DHCP server. This allows a machine
with a particular hardware address to be always allocated the same	with a particular hardware address to be always allocated the same
hostname, IP address and lease time. A hostname specified like this	hostname, IP address and lease time. A hostname specified like this
Line 848 dnsmasq to always allocate the machine lap the IP addr	Line 1123 dnsmasq to always allocate the machine lap the IP addr
192.168.0.199.	192.168.0.199.

Addresses allocated like this are not constrained to be	Addresses allocated like this are not constrained to be
in the range given by the --dhcp-range option, but they must be in	in the range given by the \fB--dhcp-range\fP option, but they must be in
the same subnet as some valid dhcp-range. For	the same subnet as some valid dhcp-range. For
subnets which don't need a pool of dynamically allocated addresses,	subnets which don't need a pool of dynamically allocated addresses,
use the "static" keyword in the dhcp-range declaration.	use the "static" keyword in the \fB--dhcp-range\fP declaration.

It is allowed to use client identifiers (called client	It is allowed to use client identifiers (called client
DUID in IPv6-land rather than	DUID in IPv6-land) rather than
hardware addresses to identify hosts by prefixing with 'id:'. Thus:	hardware addresses to identify hosts by prefixing with 'id:'. Thus:
.B --dhcp-host=id:01:02:03:04,.....	.B --dhcp-host=id:01:02:03:04,.....
refers to the host with client identifier 01:02:03:04. It is also	refers to the host with client identifier 01:02:03:04. It is also
Line 862 allowed to specify the client ID as text, like this:	Line 1137 allowed to specify the client ID as text, like this:
.B --dhcp-host=id:clientidastext,.....	.B --dhcp-host=id:clientidastext,.....

A single	A single
.B dhcp-host	.B --dhcp-host
may contain an IPv4 address or an IPv6 address, or both. IPv6 addresses must be bracketed by square brackets thus:	may contain an IPv4 address or one or more IPv6 addresses, or both. IPv6 addresses must be bracketed by square brackets thus:
.B --dhcp-host=laptop,[1234::56]	.B --dhcp-host=laptop,[1234::56]
IPv6 addresses may contain only the host-identifier part:	IPv6 addresses may contain only the host-identifier part:
.B --dhcp-host=laptop,[::56]	.B --dhcp-host=laptop,[::56]
in which case they act as wildcards in constructed dhcp ranges, with	in which case they act as wildcards in constructed DHCP ranges, with
the appropriate network part inserted.	the appropriate network part inserted. For IPv6, an address may include a prefix length:
	.B --dhcp-host=laptop,[1234:50/126]
	which (in this case) specifies four addresses, 1234::50 to 1234::53. This (an the ability
	to specify multiple addresses) is useful
	when a host presents either a consistent name or hardware-ID, but varying DUIDs, since it allows
	dnsmasq to honour the static address allocation but assign a different adddress for each DUID. This
	typically occurs when chain netbooting, as each stage of the chain gets in turn allocates an address.

Note that in IPv6 DHCP, the hardware address may not be	Note that in IPv6 DHCP, the hardware address may not be
available, though it normally is for direct-connected clients, or	available, though it normally is for direct-connected clients, or
clients using DHCP relays which support RFC 6939.	clients using DHCP relays which support RFC 6939.
Line 883 allocated to a DHCP lease, but only if a	Line 1165 allocated to a DHCP lease, but only if a
.B --dhcp-host	.B --dhcp-host
option specifying the name also exists. Only one hostname can be	option specifying the name also exists. Only one hostname can be
given in a	given in a
.B dhcp-host	.B --dhcp-host
option, but aliases are possible by using CNAMEs. (See	option, but aliases are possible by using CNAMEs. (See
.B --cname	.B --cname
).	). Note that /etc/hosts is NOT used when the DNS server side of dnsmasq
	is disabled by setting the DNS server port to zero.

	More than one
	.B --dhcp-host
	can be associated (by name, hardware address or UID) with a host. Which one is used
	(and therefore which address is allocated by DHCP and appears in the DNS) depends
	on the subnet on which the host last obtained a DHCP lease:
	the
	.B --dhcp-host
	with an address within the subnet is used. If more than one address is within the subnet,
	the result is undefined. A corollary to this is that the name associated with a host using
	.B --dhcp-host
	does not appear in the DNS until the host obtains a DHCP lease.


The special keyword "ignore"	The special keyword "ignore"
tells dnsmasq to never offer a DHCP lease to a machine. The machine	tells dnsmasq to never offer a DHCP lease to a machine. The machine
can be specified by hardware address, client ID or hostname, for	can be specified by hardware address, client ID or hostname, for
Line 898 useful when there is another DHCP server on the networ	Line 1194 useful when there is another DHCP server on the networ
be used by some machines.	be used by some machines.

The set:<tag> construct sets the tag	The set:<tag> construct sets the tag
whenever this dhcp-host directive is in use. This can be used to	whenever this \fB--dhcp-host\fP directive is in use. This can be used to
selectively send DHCP options just for this host. More than one tag	selectively send DHCP options just for this host. More than one tag
can be set in a dhcp-host directive (but not in other places where	can be set in a \fB--dhcp-host\fP directive (but not in other places where
"set:<tag>" is allowed). When a host matches any	"set:<tag>" is allowed). When a host matches any
dhcp-host directive (or one implied by /etc/ethers) then the special	\fB--dhcp-host\fP directive (or one implied by /etc/ethers) then the special
tag "known" is set. This allows dnsmasq to be configured to	tag "known" is set. This allows dnsmasq to be configured to
ignore requests from unknown machines using	ignore requests from unknown machines using
.B --dhcp-ignore=tag:!known	.B --dhcp-ignore=tag:!known
	If the host matches only a \fB--dhcp-host\fP directive which cannot
	be used because it specifies an address on different subnet, the tag "known-othernet" is set.

	The tag:<tag> construct filters which dhcp-host directives are used; more than
	one can be provided, in this case the request must match all of them. Tagged
	directives are used in preference to untagged ones. Note that one of <hwaddr>,
	<client_id> or <hostname> still needs to be specified (can be a wildcard).

Ethernet addresses (but not client-ids) may have	Ethernet addresses (but not client-ids) may have
wildcard bytes, so for example	wildcard bytes, so for example
.B --dhcp-host=00:20:e0:3b:13:*,ignore	.B --dhcp-host=00:20:e0:3b:13:*,ignore
Line 935 has both wired and wireless interfaces.	Line 1239 has both wired and wireless interfaces.
.TP	.TP
.B --dhcp-hostsfile=<path>	.B --dhcp-hostsfile=<path>
Read DHCP host information from the specified file. If a directory	Read DHCP host information from the specified file. If a directory
is given, then read all the files contained in that directory. The file contains	is given, then read all the files contained in that directory in alphabetical order. The file contains
information about one host per line. The format of a line is the same	information about one host per line. The format of a line is the same
as text to the right of '=' in --dhcp-host. The advantage of storing DHCP host information	as text to the right of '=' in \fB--dhcp-host\fP. The advantage of storing DHCP host information
in this file is that it can be changed without re-starting dnsmasq:	in this file is that it can be changed without re-starting dnsmasq:
the file will be re-read when dnsmasq receives SIGHUP.	the file will be re-read when dnsmasq receives SIGHUP.
.TP	.TP
.B --dhcp-optsfile=<path>	.B --dhcp-optsfile=<path>
Read DHCP option information from the specified file. If a directory	Read DHCP option information from the specified file. If a directory
is given, then read all the files contained in that directory. The advantage of	is given, then read all the files contained in that directory in alphabetical order. The advantage of
using this option is the same as for --dhcp-hostsfile: the	using this option is the same as for \fB--dhcp-hostsfile\fP: the
dhcp-optsfile will be re-read when dnsmasq receives SIGHUP. Note that	\fB--dhcp-optsfile\fP will be re-read when dnsmasq receives SIGHUP. Note that
it is possible to encode the information in a	it is possible to encode the information in a
.B --dhcp-boot	.B --dhcp-boot
flag as DHCP options, using the options names bootfile-name,	flag as DHCP options, using the options names bootfile-name,
server-ip-address and tftp-server. This allows these to be included	server-ip-address and tftp-server. This allows these to be included
in a dhcp-optsfile.	in a \fB--dhcp-optsfile\fP.
	.TP
	.B --dhcp-hostsdir=<path>
	This is equivalent to \fB--dhcp-hostsfile\fP, except for the following. The path MUST be a
	directory, and not an individual file. Changed or new files within
	the directory are read automatically, without the need to send SIGHUP.
	If a file is deleted or changed after it has been read by dnsmasq, then the
	host record it contained will remain until dnsmasq receives a SIGHUP, or
	is restarted; ie host records are only added dynamically. The order in which the
	files in a directory are read is not defined.
	.TP
	.B --dhcp-optsdir=<path>
	This is equivalent to \fB--dhcp-optsfile\fP, with the differences noted for \fB--dhcp-hostsdir\fP.
.TP	.TP
.B \-Z, --read-ethers	.B \-Z, --read-ethers
Read /etc/ethers for information about hosts for the DHCP server. The	Read /etc/ethers for information about hosts for the DHCP server. The
Line 982 and to set the time-server address to 192.168.0.4, do	Line 1298 and to set the time-server address to 192.168.0.4, do
or	or
.B --dhcp-option = option:ntp-server, 192.168.0.4	.B --dhcp-option = option:ntp-server, 192.168.0.4
The special address 0.0.0.0 is taken to mean "the address of the	The special address 0.0.0.0 is taken to mean "the address of the
machine running dnsmasq".	machine running dnsmasq".

	An option without data is valid, and includes just the option without data.
	(There is only one option with a zero length data field currently defined for DHCPv4, 80:rapid commit, so this feature is not very useful in practice). Options for which dnsmasq normally
	provides default values can be ommitted by defining the option with no data. These are
	netmask, broadcast, router, DNS server, domainname and hostname. Thus, for DHCPv4
	.B --dhcp-option = option:router
	will result in no router option being sent, rather than the default of the host on which dnsmasq is running. For DHCPv6, the same is true of the options DNS server and refresh time.


Data types allowed are comma separated	Data types allowed are comma separated
dotted-quad IPv4 addresses, []-wrapped IPv6 addresses, a decimal number, colon-separated hex digits	dotted-quad IPv4 addresses, []-wrapped IPv6 addresses, a decimal number, colon-separated hex digits
and a text string. If the optional tags are given then	and a text string. If the optional tags are given then
Line 1021 a literal IP address as TFTP server name, it is necess	Line 1345 a literal IP address as TFTP server name, it is necess
.B --dhcp-option=66,"1.2.3.4"	.B --dhcp-option=66,"1.2.3.4"

Encapsulated Vendor-class options may also be specified (IPv4 only) using	Encapsulated Vendor-class options may also be specified (IPv4 only) using
--dhcp-option: for instance	\fB--dhcp-option\fP: for instance
.B --dhcp-option=vendor:PXEClient,1,0.0.0.0	.B --dhcp-option=vendor:PXEClient,1,0.0.0.0
sends the encapsulated vendor	sends the encapsulated vendor
class-specific option "mftp-address=0.0.0.0" to any client whose	class-specific option "mftp-address=0.0.0.0" to any client whose
vendor-class matches "PXEClient". The vendor-class matching is	vendor-class matches "PXEClient". The vendor-class matching is
substring based (see --dhcp-vendorclass for details). If a	substring based (see \fB--dhcp-vendorclass\fP for details). If a
vendor-class option (number 60) is sent by dnsmasq, then that is used	vendor-class option (number 60) is sent by dnsmasq, then that is used
for selecting encapsulated options in preference to any sent by the	for selecting encapsulated options in preference to any sent by the
client. It is	client. It is
Line 1039 Options may be encapsulated (IPv4 only) within other o	Line 1363 Options may be encapsulated (IPv4 only) within other o
will send option 175, within which is the option 190. If multiple	will send option 175, within which is the option 190. If multiple
options are given which are encapsulated with the same option number	options are given which are encapsulated with the same option number
then they will be correctly combined into one encapsulated option.	then they will be correctly combined into one encapsulated option.
encap: and vendor: are may not both be set in the same dhcp-option.	encap: and vendor: are may not both be set in the same \fB--dhcp-option\fP.

The final variant on encapsulated options is "Vendor-Identifying	The final variant on encapsulated options is "Vendor-Identifying
Vendor Options" as specified by RFC3925. These are denoted like this:	Vendor Options" as specified by RFC3925. These are denoted like this:
Line 1061 needed, for example when sending options to PXELinux.	Line 1385 needed, for example when sending options to PXELinux.
.B --dhcp-no-override	.B --dhcp-no-override
(IPv4 only) Disable re-use of the DHCP servername and filename fields as extra	(IPv4 only) Disable re-use of the DHCP servername and filename fields as extra
option space. If it can, dnsmasq moves the boot server and filename	option space. If it can, dnsmasq moves the boot server and filename
information (from dhcp-boot) out of their dedicated fields into	information (from \fB--dhcp-boot\fP) out of their dedicated fields into
DHCP options. This make extra space available in the DHCP packet for	DHCP options. This make extra space available in the DHCP packet for
options but can, rarely, confuse old or broken clients. This flag	options but can, rarely, confuse old or broken clients. This flag
forces "simple and safe" behaviour to avoid problems in such a case.	forces "simple and safe" behaviour to avoid problems in such a case.
.TP	.TP
.B --dhcp-relay=<local address>,<server address>[,<interface]	.B --dhcp-relay=<local address>[,<server address>[#<server port>]][,<interface]
Configure dnsmasq to do DHCP relay. The local address is an address	Configure dnsmasq to do DHCP relay. The local address is an address
allocated to an interface on the host running dnsmasq. All DHCP	allocated to an interface on the host running dnsmasq. All DHCP
requests arriving on that interface will we relayed to a remote DHCP	requests arriving on that interface will we relayed to a remote DHCP
server at the server address. It is possible to relay from a single local	server at the server address. It is possible to relay from a single local
address to multiple remote servers by using multiple dhcp-relay	address to multiple remote servers by using multiple \fB--dhcp-relay\fP
configs with the same local address and different server	configs with the same local address and different server
addresses. A server address must be an IP literal address, not a	addresses. A server address must be an IP literal address, not a
domain name. In the case of DHCPv6, the server address may be the	domain name. If the server address is omitted, the request will be
ALL_SERVERS multicast address, ff05::1:3. In this case the interface	forwarded by broadcast (IPv4) or multicast (IPv6). In this case the interface
must be given, not be wildcard, and is used to direct the multicast to the	must be given and not be wildcard. The server address may specify a non-standard
correct interface to reach the DHCP server.	port to relay to. If this is used then \fB--dhcp-proxy\fP should likely also be set,
	otherwise parts of the DHCP conversation which do not pass through the relay
	will be delivered to the wrong port.

Access control for DHCP clients has the same rules as for the DHCP	Access control for DHCP clients has the same rules as for the DHCP
server, see --interface, --except-interface, etc. The optional	server, see \fB--interface\fP, \fB--except-interface\fP, etc. The optional
interface name in the dhcp-relay config has a different function: it	interface name in the \fB--dhcp-relay\fP config has a different function: it
controls on which interface DHCP replies from the server will be	controls on which interface DHCP replies from the server will be
accepted. This is intended for configurations which have three	accepted. This is intended for configurations which have three
interfaces: one being relayed from, a second connecting the DHCP	interfaces: one being relayed from, a second connecting the DHCP
Line 1097 supported: the relay function will take precedence.	Line 1423 supported: the relay function will take precedence.

Both DHCPv4 and DHCPv6 relay is supported. It's not possible to relay	Both DHCPv4 and DHCPv6 relay is supported. It's not possible to relay
DHCPv4 to a DHCPv6 server or vice-versa.	DHCPv4 to a DHCPv6 server or vice-versa.

	The DHCP relay function for IPv6 includes the ability to snoop
	prefix-delegation from relayed DHCP transactions. See
	.B --dhcp-script
	for details.
.TP	.TP
.B \-U, --dhcp-vendorclass=set:<tag>,[enterprise:<IANA-enterprise number>,]<vendor-class>	.B \-U, --dhcp-vendorclass=set:<tag>,[enterprise:<IANA-enterprise number>,]<vendor-class>
Map from a vendor-class string to a tag. Most DHCP clients provide a	Map from a vendor-class string to a tag. Most DHCP clients provide a
"vendor class" which represents, in some sense, the type of host. This option	"vendor class" which represents, in some sense, the type of host. This option
maps vendor classes to tags, so that DHCP options may be selectively delivered	maps vendor classes to tags, so that DHCP options may be selectively delivered
to different classes of hosts. For example	to different classes of hosts. For example
.B dhcp-vendorclass=set:printers,Hewlett-Packard JetDirect	.B --dhcp-vendorclass=set:printers,Hewlett-Packard JetDirect
will allow options to be set only for HP printers like so:	will allow options to be set only for HP printers like so:
.B --dhcp-option=tag:printers,3,192.168.4.4	.B --dhcp-option=tag:printers,3,192.168.4.4
The vendor-class string is	The vendor-class string is
Line 1138 normally given as colon-separated hex, but is also all	Line 1469 normally given as colon-separated hex, but is also all
simple string. If an exact match is achieved between the circuit or	simple string. If an exact match is achieved between the circuit or
agent ID and one provided by a relay agent, the tag is set.	agent ID and one provided by a relay agent, the tag is set.

.B dhcp-remoteid	.B --dhcp-remoteid
(but not dhcp-circuitid) is supported in IPv6.	(but not \fB--dhcp-circuitid\fP) is supported in IPv6.
.TP	.TP
.B --dhcp-subscrid=set:<tag>,<subscriber-id>	.B --dhcp-subscrid=set:<tag>,<subscriber-id>
(IPv4 and IPv6) Map from RFC3993 subscriber-id relay agent options to tags.	(IPv4 and IPv6) Map from RFC3993 subscriber-id relay agent options to tags.
Line 1150 a DHCP interaction to the DHCP server. Once a client i	Line 1481 a DHCP interaction to the DHCP server. Once a client i
communicates directly with the server. This is undesirable if the	communicates directly with the server. This is undesirable if the
relay agent is adding extra information to the DHCP packets, such as	relay agent is adding extra information to the DHCP packets, such as
that used by	that used by
.B dhcp-circuitid	.B --dhcp-circuitid
and	and
.B dhcp-remoteid.	.B --dhcp-remoteid.
A full relay implementation can use the RFC 5107 serverid-override	A full relay implementation can use the RFC 5107 serverid-override
option to force the DHCP server to use the relay as a full proxy, with all	option to force the DHCP server to use the relay as a full proxy, with all
packets passing through it. This flag provides an alternative method	packets passing through it. This flag provides an alternative method
Line 1168 the option is sent and matches the value. The value ma	Line 1499 the option is sent and matches the value. The value ma
"01:ff:*:02" in which case the value must match (apart from wildcards)	"01:ff:*:02" in which case the value must match (apart from wildcards)
but the option sent may have unmatched data past the end of the	but the option sent may have unmatched data past the end of the
value. The value may also be of the same form as in	value. The value may also be of the same form as in
.B dhcp-option	.B --dhcp-option
in which case the option sent is treated as an array, and one element	in which case the option sent is treated as an array, and one element
must match, so	must match, so
	.B --dhcp-match=set:efi-ia32,option:client-arch,6
--dhcp-match=set:efi-ia32,option:client-arch,6

will set the tag "efi-ia32" if the the number 6 appears in the list of	will set the tag "efi-ia32" if the the number 6 appears in the list of
architectures sent by the client in option 93. (See RFC 4578 for	architectures sent by the client in option 93. (See RFC 4578 for
details.) If the value is a string, substring matching is used.	details.) If the value is a string, substring matching is used.
Line 1182 The special form with vi-encap:<enterprise number> mat	Line 1511 The special form with vi-encap:<enterprise number> mat
vendor-identifying vendor classes for the specified enterprise. Please	vendor-identifying vendor classes for the specified enterprise. Please
see RFC 3925 for more details of these rare and interesting beasts.	see RFC 3925 for more details of these rare and interesting beasts.
.TP	.TP
	.B --dhcp-name-match=set:<tag>,<name>[*]
	Set the tag if the given name is supplied by a DHCP client. There may be a single trailing wildcard *, which has the usual meaning. Combined with dhcp-ignore or dhcp-ignore-names this gives the ability to ignore certain clients by name, or disallow certain hostnames from being claimed by a client.
	.TP
.B --tag-if=set:<tag>[,set:<tag>[,tag:<tag>[,tag:<tag>]]]	.B --tag-if=set:<tag>[,set:<tag>[,tag:<tag>[,tag:<tag>]]]
Perform boolean operations on tags. Any tag appearing as set:<tag> is set if	Perform boolean operations on tags. Any tag appearing as set:<tag> is set if
all the tags which appear as tag:<tag> are set, (or unset when tag:!<tag> is used)	all the tags which appear as tag:<tag> are set, (or unset when tag:!<tag> is used)
If no tag:<tag> appears set:<tag> tags are set unconditionally.	If no tag:<tag> appears set:<tag> tags are set unconditionally.
Any number of set: and tag: forms may appear, in any order.	Any number of set: and tag: forms may appear, in any order.
Tag-if lines ares executed in order, so if the tag in tag:<tag> is a	\fB--tag-if\fP lines are executed in order, so if the tag in tag:<tag> is a
tag set by another	tag set by another
.B tag-if,	.B --tag-if,
the line which sets the tag must precede the one which tests it.	the line which sets the tag must precede the one which tests it.

	As an extension, the tag:<tag> clauses support limited wildcard matching,
	similar to the matching in the \fB--interface\fP directive. This allows, for
	example, using \fB--tag-if=set:ppp,tag:ppp*\fP to set the tag 'ppp' for all requests
	received on any matching interface (ppp0, ppp1, etc). This can be used in conjunction
	with the tag:!<tag> format meaning that no tag matching the wildcard may be set.
.TP	.TP
.B \-J, --dhcp-ignore=tag:<tag>[,tag:<tag>]	.B \-J, --dhcp-ignore=tag:<tag>[,tag:<tag>]
When all the given tags appear in the tag set ignore the host and do	When all the given tags appear in the tag set ignore the host and do
Line 1198 not allocate it a DHCP lease.	Line 1536 not allocate it a DHCP lease.
.TP	.TP
.B --dhcp-ignore-names[=tag:<tag>[,tag:<tag>]]	.B --dhcp-ignore-names[=tag:<tag>[,tag:<tag>]]
When all the given tags appear in the tag set, ignore any hostname	When all the given tags appear in the tag set, ignore any hostname
provided by the host. Note that, unlike dhcp-ignore, it is permissible	provided by the host. Note that, unlike \fB--dhcp-ignore\fP, it is permissible
to supply no tags, in which case DHCP-client supplied hostnames	to supply no tags, in which case DHCP-client supplied hostnames
are always ignored, and DHCP hosts are added to the DNS using only	are always ignored, and DHCP hosts are added to the DNS using only
dhcp-host configuration in dnsmasq and the contents of /etc/hosts and	\fB--dhcp-host\fP configuration in dnsmasq and the contents of /etc/hosts and
/etc/ethers.	/etc/ethers.
.TP	.TP
.B --dhcp-generate-names=tag:<tag>[,tag:<tag>]	.B --dhcp-generate-names=tag:<tag>[,tag:<tag>]
Line 1246 address, and setting this flag enables this mode. Note	Line 1584 address, and setting this flag enables this mode. Note
sequential mode, clients which allow a lease to expire are much more	sequential mode, clients which allow a lease to expire are much more
likely to move IP address; for this reason it should not be generally used.	likely to move IP address; for this reason it should not be generally used.
.TP	.TP
	.B --dhcp-ignore-clid
	Dnsmasq is reading 'client identifier' (RFC 2131) option sent by clients
	(if available) to identify clients. This allow to serve same IP address
	for a host using several interfaces. Use this option to disable 'client identifier'
	reading, i.e. to always identify a host using the MAC address.
	.TP
.B --pxe-service=[tag:<tag>,]<CSA>,<menu text>[,<basename>\|<bootservicetype>][,<server address>\|<server_name>]	.B --pxe-service=[tag:<tag>,]<CSA>,<menu text>[,<basename>\|<bootservicetype>][,<server address>\|<server_name>]
Most uses of PXE boot-ROMS simply allow the PXE	Most uses of PXE boot-ROMS simply allow the PXE
system to obtain an IP address and then download the file specified by	system to obtain an IP address and then download the file specified by
.B dhcp-boot	.B --dhcp-boot
and execute it. However the PXE system is capable of more complex	and execute it. However the PXE system is capable of more complex
functions when supported by a suitable DHCP server.	functions when supported by a suitable DHCP server.

This specifies a boot option which may appear in a PXE boot menu. <CSA> is	This specifies a boot option which may appear in a PXE boot menu. <CSA> is
client system type, only services of the correct type will appear in a	client system type, only services of the correct type will appear in a
menu. The known types are x86PC, PC98, IA64_EFI, Alpha, Arc_x86,	menu. The known types are x86PC, PC98, IA64_EFI, Alpha, Arc_x86,
Intel_Lean_Client, IA32_EFI, BC_EFI, Xscale_EFI and X86-64_EFI; an	Intel_Lean_Client, IA32_EFI, x86-64_EFI, Xscale_EFI, BC_EFI, ARM32_EFI and ARM64_EFI; an
integer may be used for other types. The	integer may be used for other types. The
parameter after the menu text may be a file name, in which case dnsmasq acts as a	parameter after the menu text may be a file name, in which case dnsmasq acts as a
boot server and directs the PXE client to download the file by TFTP,	boot server and directs the PXE client to download the file by TFTP,
either from itself (	either from itself (
.B enable-tftp	.B --enable-tftp
must be set for this to work) or another TFTP server if the final server	must be set for this to work) or another TFTP server if the final server
address/name is given.	address/name is given.
Note that the "layer"	Note that the "layer"
suffix (normally ".0") is supplied by PXE, and should not be added to	suffix (normally ".0") is supplied by PXE, and need not be added to
the basename. If an integer boot service type, rather than a basename	the basename. Alternatively, the basename may be a filename, complete with suffix, in which case
	no layer suffix is added. If an integer boot service type, rather than a basename
is given, then the PXE client will search for a	is given, then the PXE client will search for a
suitable boot service for that type on the network. This search may be done	suitable boot service for that type on the network. This search may be done
by broadcast, or direct to a server if its IP address/name is provided.	by broadcast, or direct to a server if its IP address/name is provided.
Line 1282 timeout is given then after the	Line 1627 timeout is given then after the
timeout has elapsed with no keyboard input, the first available menu	timeout has elapsed with no keyboard input, the first available menu
option will be automatically executed. If the timeout is zero then the first available menu	option will be automatically executed. If the timeout is zero then the first available menu
item will be executed immediately. If	item will be executed immediately. If
.B pxe-prompt	.B --pxe-prompt
is omitted the system will wait for user input if there are multiple	is omitted the system will wait for user input if there are multiple
items in the menu, but boot immediately if	items in the menu, but boot immediately if
there is only one. See	there is only one. See
.B pxe-service	.B --pxe-service
for details of menu items.	for details of menu items.

Dnsmasq supports PXE "proxy-DHCP", in this case another DHCP server on	Dnsmasq supports PXE "proxy-DHCP", in this case another DHCP server on
the network is responsible for allocating IP addresses, and dnsmasq	the network is responsible for allocating IP addresses, and dnsmasq
simply provides the information given in	simply provides the information given in
.B pxe-prompt	.B --pxe-prompt
and	and
.B pxe-service	.B --pxe-service
to allow netbooting. This mode is enabled using the	to allow netbooting. This mode is enabled using the
.B proxy	.B proxy
keyword in	keyword in
.B dhcp-range.	.B --dhcp-range.
	.TP
	.B --dhcp-pxe-vendor=<vendor>[,...]
	According to UEFI and PXE specifications, DHCP packets between PXE clients and
	proxy PXE servers should have
	.I PXEClient
	in their vendor-class field. However, the firmware of computers from a few
	vendors is customized to carry a different identifier in that field. This option
	is used to consider such identifiers valid for identifying PXE clients. For
	instance

	.B --dhcp-pxe-vendor=PXEClient,HW-Client

	will enable dnsmasq to also provide proxy PXE service to those PXE clients with
	.I HW-Client
	in as their identifier.
.TP	.TP
.B \-X, --dhcp-lease-max=<number>	.B \-X, --dhcp-lease-max=<number>
Limits dnsmasq to the specified maximum number of DHCP leases. The	Limits dnsmasq to the specified maximum number of DHCP leases. The
Line 1315 allows dnsmasq to rebuild its lease database without e	Line 1675 allows dnsmasq to rebuild its lease database without e
reacquire a lease, if the database is lost. For DHCPv6 it sets the	reacquire a lease, if the database is lost. For DHCPv6 it sets the
priority in replies to 255 (the maximum) instead of 0 (the minimum).	priority in replies to 255 (the maximum) instead of 0 (the minimum).
.TP	.TP
	.B --dhcp-rapid-commit
	Enable DHCPv4 Rapid Commit Option specified in RFC 4039. When enabled, dnsmasq
	will respond to a DHCPDISCOVER message including a Rapid Commit
	option with a DHCPACK including a Rapid Commit option and fully committed
	address and configuration information. Should only be enabled if either the
	server is the only server for the subnet, or multiple servers are present and they each commit a binding for all clients.
	.TP
.B --dhcp-alternate-port[=<server port>[,<client port>]]	.B --dhcp-alternate-port[=<server port>[,<client port>]]
(IPv4 only) Change the ports used for DHCP from the default. If this option is	(IPv4 only) Change the ports used for DHCP from the default. If this option is
given alone, without arguments, it changes the ports used for DHCP	given alone, without arguments, it changes the ports used for DHCP
Line 1332 enables dynamic allocation. With tags, only when the t	Line 1699 enables dynamic allocation. With tags, only when the t
set. It may be repeated with different tag sets.	set. It may be repeated with different tag sets.
.TP	.TP
.B \-5, --no-ping	.B \-5, --no-ping
(IPv4 only) By default, the DHCP server will attempt to ensure that an address in	(IPv4 only) By default, the DHCP server will attempt to ensure that an address is
not in use before allocating it to a host. It does this by sending an	not in use before allocating it to a host. It does this by sending an
ICMP echo request (aka "ping") to the address in question. If it gets	ICMP echo request (aka "ping") to the address in question. If it gets
a reply, then the address must already be in use, and another is	a reply, then the address must already be in use, and another is
Line 1342 tried. This flag disables this check. Use with caution	Line 1709 tried. This flag disables this check. Use with caution
Extra logging for DHCP: log all the options sent to DHCP clients and	Extra logging for DHCP: log all the options sent to DHCP clients and
the tags used to determine them.	the tags used to determine them.
.TP	.TP
.B --quiet-dhcp, --quiet-dhcp6, --quiet-ra	.B --quiet-dhcp, --quiet-dhcp6, --quiet-ra, --quiet-tftp
Suppress logging of the routine operation of these protocols. Errors and	Suppress logging of the routine operation of these protocols. Errors and
problems will still be logged. --quiet-dhcp and quiet-dhcp6 are	problems will still be logged. \fB--quiet-tftp\fP does not consider file not
over-ridden by --log-dhcp.	found to be an error. \fB--quiet-dhcp\fP and quiet-dhcp6 are over-ridden by
	\fB--log-dhcp\fP.
.TP	.TP
.B \-l, --dhcp-leasefile=<path>	.B \-l, --dhcp-leasefile=<path>
Use the specified file to store DHCP lease information.	Use the specified file to store DHCP lease information.
Line 1357 DUID automatically when it is first needed. When given	Line 1725 DUID automatically when it is first needed. When given
provides dnsmasq the data required to create a DUID-EN type DUID. Note	provides dnsmasq the data required to create a DUID-EN type DUID. Note
that once set, the DUID is stored in the lease database, so to change between DUID-EN and	that once set, the DUID is stored in the lease database, so to change between DUID-EN and
automatically created DUIDs or vice-versa, the lease database must be	automatically created DUIDs or vice-versa, the lease database must be
re-intialised. The enterprise-id is assigned by IANA, and the uid is a	re-initialised. The enterprise-id is assigned by IANA, and the uid is a
string of hex octets unique to a particular device.	string of hex octets unique to a particular device.
.TP	.TP
.B \-6 --dhcp-script=<path>	.B \-6 --dhcp-script=<path>
Line 1371 address of the host (or DUID for IPv6) , the IP addres	Line 1739 address of the host (or DUID for IPv6) , the IP addres
if known. "add" means a lease has been created, "del" means it has	if known. "add" means a lease has been created, "del" means it has
been destroyed, "old" is a notification of an existing lease when	been destroyed, "old" is a notification of an existing lease when
dnsmasq starts or a change to MAC address or hostname of an existing	dnsmasq starts or a change to MAC address or hostname of an existing
lease (also, lease length or expiry and client-id, if leasefile-ro is set).	lease (also, lease length or expiry and client-id, if \fB--leasefile-ro\fP is set
	and lease expiry if \fB--script-on-renewal\fP is set).
If the MAC address is from a network type other than ethernet,	If the MAC address is from a network type other than ethernet,
it will have the network type prepended, eg "06-01:23:45:67:89:ab" for	it will have the network type prepended, eg "06-01:23:45:67:89:ab" for
token ring. The process is run as root (assuming that dnsmasq was originally run as	token ring. The process is run as root (assuming that dnsmasq was originally run as
Line 1394 If dnsmasq was compiled with HAVE_BROKEN_RTC, then	Line 1763 If dnsmasq was compiled with HAVE_BROKEN_RTC, then
the length of the lease (in seconds) is stored in	the length of the lease (in seconds) is stored in
DNSMASQ_LEASE_LENGTH, otherwise the time of lease expiry is stored in	DNSMASQ_LEASE_LENGTH, otherwise the time of lease expiry is stored in
DNSMASQ_LEASE_EXPIRES. The number of seconds until lease expiry is	DNSMASQ_LEASE_EXPIRES. The number of seconds until lease expiry is
always stored in DNSMASQ_TIME_REMAINING.	always stored in DNSMASQ_TIME_REMAINING.

	DNSMASQ_DATA_MISSING is set to "1" during "old" events for existing
	leases generated at startup to indicate that data not stored in the
	persistent lease database will not be present. This comprises everything
	other than IP address, hostname, MAC address, DUID, IAID and lease length
	or expiry time.

If a lease used to have a hostname, which is	If a lease used to have a hostname, which is
removed, an "old" event is generated with the new state of the lease,	removed, an "old" event is generated with the new state of the lease,
ie no name, and the former name is provided in the environment	ie no name, and the former name is provided in the environment
Line 1416 DNSMASQ_LOG_DHCP is set if	Line 1791 DNSMASQ_LOG_DHCP is set if
.B --log-dhcp	.B --log-dhcp
is in effect.	is in effect.

	DNSMASQ_REQUESTED_OPTIONS a string containing the decimal values in the Parameter Request List option, comma separated, if the parameter request list option is provided by the client.

	DNSMASQ_MUD_URL the Manufacturer Usage Description URL if provided by the client. (See RFC8520 for details.)


For IPv4 only:	For IPv4 only:

DNSMASQ_CLIENT_ID if the host provided a client-id.	DNSMASQ_CLIENT_ID if the host provided a client-id.
Line 1448 database.	Line 1828 database.


All file descriptors are	All file descriptors are
closed except stdin, stdout and stderr which are open to /dev/null	closed except stdin, which is open to /dev/null, and stdout and stderr which capture output for logging by dnsmasq.
(except in debug mode).	(In debug mode, stdio, stdout and stderr file are left as those inherited from the invoker of dnsmasq).

The script is not invoked concurrently: at most one instance	The script is not invoked concurrently: at most one instance
of the script is ever running (dnsmasq waits for an instance of script to exit	of the script is ever running (dnsmasq waits for an instance of script to exit
Line 1464 At dnsmasq startup, the script will be invoked for	Line 1844 At dnsmasq startup, the script will be invoked for
all existing leases as they are read from the lease file. Expired	all existing leases as they are read from the lease file. Expired
leases will be called with "del" and others with "old". When dnsmasq	leases will be called with "del" and others with "old". When dnsmasq
receives a HUP signal, the script will be invoked for existing leases	receives a HUP signal, the script will be invoked for existing leases
with an "old " event.	with an "old" event.


There are two further actions which may appear as the first argument	There are five further actions which may appear as the first argument
to the script, "init" and "tftp". More may be added in the future, so	to the script, "init", "arp-add", "arp-del", "relay-snoop" and "tftp".
	More may be added in the future, so
scripts should be written to ignore unknown actions. "init" is	scripts should be written to ignore unknown actions. "init" is
described below in	described below in
.B --leasefile-ro	.B --leasefile-ro

The "tftp" action is invoked when a TFTP file transfer completes: the	The "tftp" action is invoked when a TFTP file transfer completes: the
arguments are the file size in bytes, the address to which the file	arguments are the file size in bytes, the address to which the file
was sent, and the complete pathname of the file.	was sent, and the complete pathname of the file.

	The "relay-snoop" action is invoked when dnsmasq is configured as a DHCP
	relay for DHCPv6 and it relays a prefx delegation to a client. The arguments
	are the name of the interface where the client is conected, its (link-local)
	address on that interface and the delegated prefix. This information is
	sufficient to install routes to the delegated prefix of a router. See
	.B --dhcp-relay
	for more details on configuring DHCP relay.

	The "arp-add" and "arp-del" actions are only called if enabled with
	.B --script-arp
	They are are supplied with a MAC address and IP address as arguments. "arp-add" indicates
	the arrival of a new entry in the ARP or neighbour table, and "arp-del" indicates the deletion of same.

.TP	.TP
.B --dhcp-luascript=<path>	.B --dhcp-luascript=<path>
Specify a script written in Lua, to be run when leases are created,	Specify a script written in Lua, to be run when leases are created,
destroyed or changed. To use this option, dnsmasq must be compiled	destroyed or changed. To use this option, dnsmasq must be compiled
with the correct support. The Lua interpreter is intialised once, when	with the correct support. The Lua interpreter is initialised once, when
dnsmasq starts, so that global variables persist between lease	dnsmasq starts, so that global variables persist between lease
events. The Lua code must define a	events. The Lua code must define a
.B lease	.B lease
Line 1522 table holds the tags	Line 1917 table holds the tags
.B file_name	.B file_name
and	and
.B file_size.	.B file_size.

	The
	.B arp
	and
	.B arp-old
	functions are called only when enabled with
	.B --script-arp
	and have a table which holds the tags
	.B mac_address
	and
	.B client_address.
.TP	.TP
.B --dhcp-scriptuser	.B --dhcp-scriptuser
Specify the user as which to run the lease-change script or Lua script. This defaults to root, but can be changed to another user using this flag.	Specify the user as which to run the lease-change script or Lua script. This defaults to root, but can be changed to another user using this flag.
.TP	.TP
	.B --script-arp
	Enable the "arp" and "arp-old" functions in the \fB--dhcp-script\fP and \fB--dhcp-luascript\fP.
	.TP
.B \-9, --leasefile-ro	.B \-9, --leasefile-ro
Completely suppress use of the lease database file. The file will not	Completely suppress use of the lease database file. The file will not
be created, read, or written. Change the way the lease-change	be created, read, or written. Change the way the lease-change
Line 1540 stdout and exit with zero exit code. Setting this	Line 1949 stdout and exit with zero exit code. Setting this
option also forces the leasechange script to be called on changes	option also forces the leasechange script to be called on changes
to the client-id and lease length and expiry time.	to the client-id and lease length and expiry time.
.TP	.TP
	.B --script-on-renewal
	Call the DHCP script when the lease expiry time changes, for instance when the
	lease is renewed.
	.TP
.B --bridge-interface=<interface>,<alias>[,<alias>]	.B --bridge-interface=<interface>,<alias>[,<alias>]
Treat DHCP request packets arriving at any of the <alias> interfaces	Treat DHCP (v4 and v6) requests and IPv6 Router Solicit packets
as if they had arrived at <interface>. This option is necessary when	arriving at any of the <alias> interfaces as if they had arrived at
using "old style" bridging on BSD platforms, since	<interface>. This option allows dnsmasq to provide DHCP and RA
packets arrive at tap interfaces which don't have an IP address.	service over unaddressed and unbridged Ethernet interfaces, e.g. on an
	OpenStack compute host where each such interface is a TAP interface to
	a VM, or as in "old style bridging" on BSD platforms. A trailing '*'
	wildcard can be used in each <alias>.

	It is permissible to add more than one alias using more than one \fB--bridge-interface\fP option since
	\fB--bridge-interface=int1,alias1,alias2\fP is exactly equivalent to
	\fB--bridge-interface=int1,alias1 --bridge-interface=int1,alias2\fP
.TP	.TP
.B \-s, --domain=<domain>[,<address range>[,local]]	.B --shared-network=<interface>,<addr>
	.PD 0
	.TP
	.B --shared-network=<addr>,<addr>
	.PD 1v
	The DHCP server determines which DHCP ranges are useable for allocating an
	address to a DHCP client based on the network from which the DHCP request arrives,
	and the IP configuration of the server's interface on that network. The shared-network
	option extends the available subnets (and therefore DHCP ranges) beyond the
	subnets configured on the arrival interface.

	The first argument is either the
	name of an interface, or an address that is configured on a local interface, and the
	second argument is an address which defines another subnet on which addresses can be allocated.

	To be useful, there must be a suitable dhcp-range which allows address allocation on this subnet
	and this dhcp-range MUST include the netmask.

	Using shared-network also needs extra
	consideration of routing. Dnsmasq does not have the usual information that it uses to
	determine the default route, so the default route option (or other routing) MUST be
	configured manually. The client must have a route to the server: if the two-address form
	of shared-network is used, this needs to be to the first specified address. If the interface,address
	form is used, there must be a route to all of the addresses configured on the interface.

	The two-address form of shared-network is also usable with a DHCP relay: the first address
	is the address of the relay and the second, as before, specifies an extra subnet which
	addresses may be allocated from.

	.TP
	.B \-s, --domain=<domain>[[,<address range>[,local]]\|<interface>]
Specifies DNS domains for the DHCP server. Domains may be be given	Specifies DNS domains for the DHCP server. Domains may be be given
unconditionally (without the IP range) or for limited IP ranges. This has two effects;	unconditionally (without the IP range) or for limited IP ranges. This has two effects;
firstly it causes the DHCP server to return the domain to any hosts	firstly it causes the DHCP server to return the domain to any hosts
which request it, and secondly it sets the domain which it is legal	which request it, and secondly it sets the domain which it is legal
for DHCP-configured hosts to claim. The intention is to constrain	for DHCP-configured hosts to claim. The intention is to constrain
hostnames so that an untrusted host on the LAN cannot advertise	hostnames so that an untrusted host on the LAN cannot advertise
its name via dhcp as e.g. "microsoft.com" and capture traffic not	its name via DHCP as e.g. "microsoft.com" and capture traffic not
meant for it. If no domain suffix is specified, then any DHCP	meant for it. If no domain suffix is specified, then any DHCP
hostname with a domain part (ie with a period) will be disallowed	hostname with a domain part (ie with a period) will be disallowed
and logged. If suffix is specified, then hostnames with a domain	and logged. If suffix is specified, then hostnames with a domain
Line 1575 which can change the behaviour of dnsmasq with domains	Line 2025 which can change the behaviour of dnsmasq with domains

If the address range is given as ip-address/network-size, then a	If the address range is given as ip-address/network-size, then a
additional flag "local" may be supplied which has the effect of adding	additional flag "local" may be supplied which has the effect of adding
--local declarations for forward and reverse DNS queries. Eg.	\fB--local\fP declarations for forward and reverse DNS queries. Eg.
.B --domain=thekelleys.org.uk,192.168.0.0/24,local	.B --domain=thekelleys.org.uk,192.168.0.0/24,local
is identical to	is identical to
.B --domain=thekelleys.org.uk,192.168.0.0/24	.B --domain=thekelleys.org.uk,192.168.0.0/24
--local=/thekelleys.org.uk/ --local=/0.168.192.in-addr.arpa/	.B --local=/thekelleys.org.uk/ --local=/0.168.192.in-addr.arpa/
The network size must be 8, 16 or 24 for this to be legal.
	The address range can also be given as a network interface name, in which case
	all of the subnets currently assigned to the interface are used in matching the
	address. This allows hosts on different physical subnets to be given different
	domains in a way which updates automatically as the interface addresses change.
.TP	.TP
.B --dhcp-fqdn	.B --dhcp-fqdn
In the default mode, dnsmasq inserts the unqualified names of	In the default mode, dnsmasq inserts the unqualified names of
Line 1614 discovery and (possibly) prefix discovery for autonomo	Line 2068 discovery and (possibly) prefix discovery for autonomo
creation are handled by a different protocol. When DHCP is in use,	creation are handled by a different protocol. When DHCP is in use,
only a subset of this is needed, and dnsmasq can handle it, using	only a subset of this is needed, and dnsmasq can handle it, using
existing DHCP configuration to provide most data. When RA is enabled,	existing DHCP configuration to provide most data. When RA is enabled,
dnsmasq will advertise a prefix for each dhcp-range, with default	dnsmasq will advertise a prefix for each \fB--dhcp-range\fP, with default
router and recursive DNS server as the relevant link-local address on	router as the relevant link-local address on
the machine running dnsmasq. By default, he "managed address" bits are set, and	the machine running dnsmasq. By default, the "managed address" bits are set, and
the "use SLAAC" bit is reset. This can be changed for individual	the "use SLAAC" bit is reset. This can be changed for individual
subnets with the mode keywords described in	subnets with the mode keywords described in
.B --dhcp-range.	.B --dhcp-range.
RFC6106 DNS parameters are included in the advertisements. By default,	RFC6106 DNS parameters are included in the advertisements. By default,
the relevant link-local address of the machine running dnsmasq is sent	the relevant link-local address of the machine running dnsmasq is sent
as recursive DNS server. If provided, the DHCPv6 options dns-server and	as recursive DNS server. If provided, the DHCPv6 options dns-server and
domain-search are used for RDNSS and DNSSL.	domain-search are used for the DNS server (RDNSS) and the domain search list (DNSSL).
.TP	.TP
.B --ra-param=<interface>,[high\|low],[[<ra-interval>],<router lifetime>]	.B --ra-param=<interface>,[mtu:<integer>\|<interface>\|off,][high,\|low,]<ra-interval>[,<router lifetime>]
Set non-default values for router advertisements sent via an	Set non-default values for router advertisements sent via an
interface. The priority field for the router may be altered from the	interface. The priority field for the router may be altered from the
default of medium with eg	default of medium with eg
Line 1634 The interval between router advertisements may be set	Line 2088 The interval between router advertisements may be set
.B --ra-param=eth0,60.	.B --ra-param=eth0,60.
The lifetime of the route may be changed or set to zero, which allows	The lifetime of the route may be changed or set to zero, which allows
a router to advertise prefixes but not a route via itself.	a router to advertise prefixes but not a route via itself.
.B --ra-parm=eth0,0,0	.B --ra-param=eth0,0,0
(A value of zero for the interval means the default value.) All three parameters may be set at once.	(A value of zero for the interval means the default value.) All four parameters may be set at once.
.B --ra-param=low,60,1200	.B --ra-param=eth0,mtu:1280,low,60,1200

The interface field may include a wildcard.	The interface field may include a wildcard.

	The mtu: parameter may be an arbitrary interface name, in which case the MTU value for that interface is used. This is useful
	for (eg) advertising the MTU of a WAN interface on the other interfaces of a router.
.TP	.TP
	.B --dhcp-reply-delay=[tag:<tag>,]<integer>
	Delays sending DHCPOFFER and PROXYDHCP replies for at least the specified number of seconds.
	This can be used as workaround for bugs in PXE boot firmware that does not function properly when
	receiving an instant reply.
	This option takes into account the time already spent waiting (e.g. performing ping check) if any.
	.TP
.B --enable-tftp[=<interface>[,<interface>]]	.B --enable-tftp[=<interface>[,<interface>]]
Enable the TFTP server function. This is deliberately limited to that	Enable the TFTP server function. This is deliberately limited to that
needed to net-boot a client. Only reading is allowed; the tsize and	needed to net-boot a client. Only reading is allowed; the tsize and
blksize extensions are supported (tsize is only supported in octet	blksize extensions are supported (tsize is only supported in octet
mode). Without an argument, the TFTP service is provided to the same set of interfaces as DHCP service.	mode). Without an argument, the TFTP service is provided to the same set of interfaces as DHCP service.
If the list of interfaces is provided, that defines which interfaces recieve TFTP service.	If the list of interfaces is provided, that defines which interfaces receive TFTP service.
.TP	.TP
.B --tftp-root=<directory>[,<interface>]	.B --tftp-root=<directory>[,<interface>]
Look for files to transfer using TFTP relative to the given	Look for files to transfer using TFTP relative to the given
Line 1654 Absolute paths (starting with /) are allowed, but they	Line 2118 Absolute paths (starting with /) are allowed, but they
the tftp-root. If the optional interface argument is given, the	the tftp-root. If the optional interface argument is given, the
directory is only used for TFTP requests via that interface.	directory is only used for TFTP requests via that interface.
.TP	.TP
.B --tftp-unique-root	.B --tftp-no-fail
Add the IP address of the TFTP client as a path component on the end	Do not abort startup if specified tftp root directories are inaccessible.
of the TFTP-root (in standard dotted-quad format). Only valid if a
tftp-root is set and the directory exists. For instance, if tftp-root is "/tftp" and client
1.2.3.4 requests file "myfile" then the effective path will be
"/tftp/1.2.3.4/myfile" if /tftp/1.2.3.4 exists or /tftp/myfile otherwise.
.TP	.TP
	.B --tftp-unique-root[=ip\|mac]
	Add the IP or hardware address of the TFTP client as a path component on the end
	of the TFTP-root. Only valid if a \fB--tftp-root\fP is set and the directory exists.
	Defaults to adding IP address (in standard dotted-quad format).
	For instance, if \fB--tftp-root\fP is "/tftp" and client 1.2.3.4 requests file "myfile"
	then the effective path will be "/tftp/1.2.3.4/myfile" if /tftp/1.2.3.4 exists or /tftp/myfile otherwise.
	When "=mac" is specified it will append the MAC address instead, using lowercase zero padded digits
	separated by dashes, e.g.: 01-02-03-04-aa-bb
	Note that resolving MAC addresses is only possible if the client is in the local network or obtained
	a DHCP lease from us.
	.TP
.B --tftp-secure	.B --tftp-secure
Enable TFTP secure mode: without this, any file which is readable by	Enable TFTP secure mode: without this, any file which is readable by
the dnsmasq process under normal unix access-control rules is	the dnsmasq process under normal unix access-control rules is
available via TFTP. When the --tftp-secure flag is given, only files	available via TFTP. When the \fB--tftp-secure\fP flag is given, only files
owned by the user running the dnsmasq process are accessible. If	owned by the user running the dnsmasq process are accessible. If
dnsmasq is being run as root, different rules apply: --tftp-secure	dnsmasq is being run as root, different rules apply: \fB--tftp-secure\fP
has no effect, but only files which have the world-readable bit set	has no effect, but only files which have the world-readable bit set
are accessible. It is not recommended to run dnsmasq as root with TFTP	are accessible. It is not recommended to run dnsmasq as root with TFTP
enabled, and certainly not without specifying --tftp-root. Doing so	enabled, and certainly not without specifying \fB--tftp-root\fP. Doing so
can expose any world-readable file on the server to any host on the net.	can expose any world-readable file on the server to any host on the net.
.TP	.TP
.B --tftp-lowercase	.B --tftp-lowercase
Line 1690 require about (2*n) + 10 descriptors. If	Line 2161 require about (2*n) + 10 descriptors. If
.B --tftp-port-range	.B --tftp-port-range
is given, that can affect the number of concurrent connections.	is given, that can affect the number of concurrent connections.
.TP	.TP
	.B --tftp-mtu=<mtu size>
	Use size as the ceiling of the MTU supported by the intervening network when
	negotiating TFTP blocksize, overriding the MTU setting of the local interface if it is larger.
	.TP
.B --tftp-no-blocksize	.B --tftp-no-blocksize
Stop the TFTP server from negotiating the "blocksize" option with a	Stop the TFTP server from negotiating the "blocksize" option with a
client. Some buggy clients request this option but then behave badly	client. Some buggy clients request this option but then behave badly
Line 1703 specifies a range of ports for use by TFTP transfers.	Line 2178 specifies a range of ports for use by TFTP transfers.
useful when TFTP has to traverse a firewall. The start of the range	useful when TFTP has to traverse a firewall. The start of the range
cannot be lower than 1025 unless dnsmasq is running as root. The number	cannot be lower than 1025 unless dnsmasq is running as root. The number
of concurrent TFTP connections is limited by the size of the port range.	of concurrent TFTP connections is limited by the size of the port range.
.TP	.TP
	.B --tftp-single-port
	Run in a mode where the TFTP server uses ONLY the well-known port (69) for its end
	of the TFTP transfer. This allows TFTP to work when there in NAT is the path between client and server. Note that
	this is not strictly compliant with the RFCs specifying the TFTP protocol: use at your own risk.
	.TP
.B \-C, --conf-file=<file>	.B \-C, --conf-file=<file>
Specify a different configuration file. The conf-file option is also allowed in	Specify a configuration file. The presence of this option stops dnsmasq from reading the default configuration
configuration files, to include multiple configuration files. A	file (normally /etc/dnsmasq.conf). Multiple files may be specified by repeating the option
	either on the command line or in configuration files. A
filename of "-" causes dnsmasq to read configuration from stdin.	filename of "-" causes dnsmasq to read configuration from stdin.
.TP	.TP
.B \-7, --conf-dir=<directory>[,<file-extension>......]	.B \-7, --conf-dir=<directory>[,<file-extension>......],
Read all the files in the given directory as configuration	Read all the files in the given directory as configuration
files. If extension(s) are given, any files which end in those	files. If extension(s) are given, any files which end in those
extensions are skipped. Any files whose names end in ~ or start with . or start and end	extensions are skipped. Any files whose names end in ~ or start with . or start and end
with # are always skipped. This flag may be given on the command	with # are always skipped. If the extension starts with * then only files
line or in a configuration file.	which have that extension are loaded. So
	.B --conf-dir=/path/to/dir,*.conf
	loads all files with the suffix .conf in /path/to/dir. This flag may be given on the command
	line or in a configuration file. If giving it on the command line, be sure to
	escape * characters. Files are loaded in alphabetical order of filename.
.TP	.TP
.B --servers-file=<file>	.B --servers-file=<file>
A special case of	A special case of
.B --conf-file	.B --conf-file
which differs in two respects. Firstly, only --server and --rev-server are allowed	which differs in two respects. Firstly, only \fB--server\fP and \fB--rev-server\fP are allowed
in the configuration file included. Secondly, the file is re-read and the configuration	in the configuration file included. Secondly, the file is re-read and the configuration
therein is updated when dnsmasq recieves SIGHUP.	therein is updated when dnsmasq receives SIGHUP.
	.TP
	.B \--conf-script=<file>[ <arg]
	Execute <file>, and treat what it emits to stdout as the contents of a configuration file.
	If the script exits with a non-zero exit code, dnsmasq treats this as a fatal error.
	The script can be passed arguments, space seperated from the filename and each other so, for instance
	.B --conf-dir="/etc/dnsmasq-uncompress-ads /share/ads-domains.gz"

	with /etc/dnsmasq-uncompress-ads containing

	set -e

	zcat ${1} \| sed -e "s:^:address=/:" -e "s:$:/:"

	exit 0

	and /share/ads-domains.gz containing a compressed
	list of ad server domains will save disk space with large ad-server blocklists.
	.TP
	.B --no-ident
	Do not respond to class CHAOS and type TXT in domain bind queries.

	Without this option being set, the cache statistics are also available in the
	DNS as answers to queries of class CHAOS and type TXT in domain bind. The domain
	names are cachesize.bind, insertions.bind, evictions.bind, misses.bind,
	hits.bind, auth.bind and servers.bind unless disabled at compile-time. An
	example command to query this, using the
	.B dig
	utility would be

	dig +short chaos txt cachesize.bind

.SH CONFIG FILE	.SH CONFIG FILE
At startup, dnsmasq reads	At startup, dnsmasq reads
.I /etc/dnsmasq.conf,	.I /etc/dnsmasq.conf,
Line 1729 if it exists. (On	Line 2245 if it exists. (On
FreeBSD, the file is	FreeBSD, the file is
.I /usr/local/etc/dnsmasq.conf	.I /usr/local/etc/dnsmasq.conf
) (but see the	) (but see the
.B \-C	.B \--conf-file
and	and
.B \-7	.B \--conf-dir
options.) The format of this	options.) The format of this
file consists of one option per line, exactly as the long options detailed	file consists of one option per line, exactly as the long options detailed
in the OPTIONS section but without the leading "--". Lines starting with # are comments and ignored. For	in the OPTIONS section but without the leading "--". Lines starting with # are comments and ignored. For
Line 1747 clears its cache and then re-loads	Line 2263 clears its cache and then re-loads
.I /etc/hosts	.I /etc/hosts
and	and
.I /etc/ethers	.I /etc/ethers
and any file given by --dhcp-hostsfile, --dhcp-optsfile or --addn-hosts.	and any file given by \fB--dhcp-hostsfile\fP, \fB--dhcp-hostsdir\fP, \fB--dhcp-optsfile\fP,
The dhcp lease change script is called for all	\fB--dhcp-optsdir\fP, \fB--addn-hosts\fP or \fB--hostsdir\fP.
	The DHCP lease change script is called for all
existing DHCP leases. If	existing DHCP leases. If
.B	.B
--no-poll	--no-poll
Line 1767 misses and the number of authoritative queries answere	Line 2284 misses and the number of authoritative queries answere
server it gives the number of queries sent, and the number which	server it gives the number of queries sent, and the number which
resulted in an error. In	resulted in an error. In
.B --no-daemon	.B --no-daemon
mode or when full logging is enabled (-q), a complete dump of the	mode or when full logging is enabled (\fB--log-queries\fP), a complete dump of the
contents of the cache is made.	contents of the cache is made.

The cache statistics are also available in the DNS as answers to
queries of class CHAOS and type TXT in domain bind. The domain names are cachesize.bind, insertions.bind, evictions.bind,
misses.bind, hits.bind, auth.bind and servers.bind. An example command to query this, using the
.B dig
utility would be

dig +short chaos txt cachesize.bind

.PP
When it receives SIGUSR2 and it is logging direct to a file (see	When it receives SIGUSR2 and it is logging direct to a file (see
.B --log-facility	.B --log-facility
)	)
Line 1800 and	Line 2308 and


.PP	.PP
Dnsmasq is a DNS query forwarder: it it not capable of recursively	Dnsmasq is a DNS query forwarder: it is not capable of recursively
answering arbitrary queries starting from the root servers but	answering arbitrary queries starting from the root servers but
forwards such queries to a fully recursive upstream DNS server which is	forwards such queries to a fully recursive upstream DNS server which is
typically provided by an ISP. By default, dnsmasq reads	typically provided by an ISP. By default, dnsmasq reads
Line 1848 using	Line 2356 using
options or put their addresses real in another file, say	options or put their addresses real in another file, say
.I /etc/resolv.dnsmasq	.I /etc/resolv.dnsmasq
and run dnsmasq with the	and run dnsmasq with the
.B \-r /etc/resolv.dnsmasq	.B \--resolv-file /etc/resolv.dnsmasq
option. This second technique allows for dynamic update of the server	option. This second technique allows for dynamic update of the server
addresses by PPP or DHCP.	addresses by PPP or DHCP.
.PP	.PP
Line 1866 the CNAME is shadowed too.	Line 2374 the CNAME is shadowed too.
The tag system works as follows: For each DHCP request, dnsmasq	The tag system works as follows: For each DHCP request, dnsmasq
collects a set of valid tags from active configuration lines which	collects a set of valid tags from active configuration lines which
include set:<tag>, including one from the	include set:<tag>, including one from the
.B dhcp-range	.B --dhcp-range
used to allocate the address, one from any matching	used to allocate the address, one from any matching
.B dhcp-host	.B --dhcp-host
(and "known" if a dhcp-host matches)	(and "known" or "known-othernet" if a \fB--dhcp-host\fP matches)
The tag "bootp" is set for BOOTP requests, and a tag whose name is the	The tag "bootp" is set for BOOTP requests, and a tag whose name is the
name of the interface on which the request arrived is also set.	name of the interface on which the request arrived is also set.

Any configuration lines which include one or more tag:<tag> constructs	Any configuration lines which include one or more tag:<tag> constructs
will only be valid if all that tags are matched in the set derived	will only be valid if all that tags are matched in the set derived
above. Typically this is dhcp-option.	above. Typically this is \fB--dhcp-option\fP.
.B dhcp-option	.B --dhcp-option
which has tags will be used in preference to an untagged	which has tags will be used in preference to an untagged
.B dhcp-option,	.B --dhcp-option,
provided that _all_ the tags match somewhere in the	provided that _all_ the tags match somewhere in the
set collected as described above. The prefix '!' on a tag means 'not'	set collected as described above. The prefix '!' on a tag means 'not'
so --dhcp-option=tag:!purple,3,1.2.3.4 sends the option when the	so \fB--dhcp-option=tag:!purple,3,1.2.3.4\fP sends the option when the
tag purple is not in the set of valid tags. (If using this in a	tag purple is not in the set of valid tags. (If using this in a
command line rather than a configuration file, be sure to escape !,	command line rather than a configuration file, be sure to escape !,
which is a shell metacharacter)	which is a shell metacharacter)

When selecting dhcp-options, a tag from dhcp-range is second class	When selecting \fB--dhcp-options\fP, a tag from \fB--dhcp-range\fP is second class
relative to other tags, to make it easy to override options for	relative to other tags, to make it easy to override options for
individual hosts, so	individual hosts, so
.B dhcp-range=set:interface1,......	.B --dhcp-range=set:interface1,......
.B dhcp-host=set:myhost,.....	.B --dhcp-host=set:myhost,.....
.B dhcp-option=tag:interface1,option:nis-domain,"domain1"	.B --dhcp-option=tag:interface1,option:nis-domain,"domain1"
.B dhcp-option=tag:myhost,option:nis-domain,"domain2"	.B --dhcp-option=tag:myhost,option:nis-domain,"domain2"
will set the NIS-domain to domain1 for hosts in the range, but	will set the NIS-domain to domain1 for hosts in the range, but
override that to domain2 for a particular host.	override that to domain2 for a particular host.

.PP	.PP
Note that for	Note that for
.B dhcp-range	.B --dhcp-range
both tag:<tag> and set:<tag> are allowed, to both select the range in	both tag:<tag> and set:<tag> are allowed, to both select the range in
use based on (eg) dhcp-host, and to affect the options sent, based on	use based on (eg) \fB--dhcp-host\fP, and to affect the options sent, based on
the range selected.	the range selected.

This system evolved from an earlier, more limited one and for backward	This system evolved from an earlier, more limited one and for backward
compatibility "net:" may be used instead of "tag:" and "set:" may be	compatibility "net:" may be used instead of "tag:" and "set:" may be
omitted. (Except in	omitted. (Except in
.B dhcp-host,	.B --dhcp-host,
where "net:" may be used instead of "set:".) For the same reason, '#'	where "net:" may be used instead of "set:".) For the same reason, '#'
may be used instead of '!' to indicate NOT.	may be used instead of '!' to indicate NOT.
.PP	.PP
The DHCP server in dnsmasq will function as a BOOTP server also,	The DHCP server in dnsmasq will function as a BOOTP server also,
provided that the MAC address and IP address for clients are given,	provided that the MAC address and IP address for clients are given,
either using	either using
.B dhcp-host	.B --dhcp-host
configurations or in	configurations or in
.I /etc/ethers	.I /etc/ethers
, and a	, and a
.B dhcp-range	.B --dhcp-range
configuration option is present to activate the DHCP server	configuration option is present to activate the DHCP server
on a particular network. (Setting --bootp-dynamic removes the need for	on a particular network. (Setting \fB--bootp-dynamic\fP removes the need for
static address mappings.) The filename	static address mappings.) The filename
parameter in a BOOTP request is used as a tag,	parameter in a BOOTP request is used as a tag,
as is the tag "bootp", allowing some control over the options returned to	as is the tag "bootp", allowing some control over the options returned to
different classes of hosts.	different classes of hosts.

.SH AUTHORITATIVE CONFIGURATION	.SH AUTHORITATIVE CONFIGURATION
.PP
Configuring dnsmasq to act as an authoritative DNS server is	Configuring dnsmasq to act as an authoritative DNS server is
complicated by the fact that it involves configuration of external DNS	complicated by the fact that it involves configuration of external DNS
servers to provide delegation. We will walk through three scenarios of	servers to provide delegation. We will walk through three scenarios of
Line 1940 for which dnsmasq is authoritative our.zone.com.	Line 2447 for which dnsmasq is authoritative our.zone.com.
The simplest configuration consists of two lines of dnsmasq configuration; something like	The simplest configuration consists of two lines of dnsmasq configuration; something like

.nf	.nf
.B auth-server=server.example.com,eth0	.B --auth-server=server.example.com,eth0
.B auth-zone=our.zone.com,1.2.3.0/24	.B --auth-zone=our.zone.com,1.2.3.0/24
.fi	.fi

and two records in the external DNS	and two records in the external DNS
Line 1964 authoritative zone which dnsmasq is serving, typically	Line 2471 authoritative zone which dnsmasq is serving, typically
we have	we have

.nf	.nf
.B auth-server=our.zone.com,eth0	.B --auth-server=our.zone.com,eth0
.B auth-zone=our.zone.com,1.2.3.0/24	.B --auth-zone=our.zone.com,1.2.3.0/24
.fi	.fi

.nf	.nf
Line 1984 entry or	Line 2491 entry or
.B --host-record.	.B --host-record.

.nf	.nf
.B auth-server=our.zone.com,eth0	.B --auth-server=our.zone.com,eth0
.B host-record=our.zone.com,1.2.3.4	.B --host-record=our.zone.com,1.2.3.4
.B auth-zone=our.zone.com,1.2.3.0/24	.B --auth-zone=our.zone.com,1.2.3.0/24
.fi	.fi

If the external address is dynamic, the address	If the external address is dynamic, the address
associated with our.zone.com must be derived from the address of the	associated with our.zone.com must be derived from the address of the
relevant interface. This is done using	relevant interface. This is done using
.B interface-name	.B --interface-name
Something like:	Something like:

.nf	.nf
.B auth-server=our.zone.com,eth0	.B --auth-server=our.zone.com,eth0
.B interface-name=our.zone.com,eth0	.B --interface-name=our.zone.com,eth0
.B auth-zone=our.zone.com,1.2.3.0/24,eth0	.B --auth-zone=our.zone.com,1.2.3.0/24,eth0
.fi	.fi

(The "eth0" argument in auth-zone adds the subnet containing eth0's	(The "eth0" argument in \fB--auth-zone\fP adds the subnet containing eth0's
dynamic address to the zone, so that the interface-name returns the	dynamic address to the zone, so that the \fB--interface-name\fP returns the
address in outside queries.)	address in outside queries.)

Our final configuration builds on that above, but also adds a	Our final configuration builds on that above, but also adds a
Line 2013 secondary is beyond the scope of this man-page, but th	Line 2520 secondary is beyond the scope of this man-page, but th
configuration of dnsmasq is simple:	configuration of dnsmasq is simple:

.nf	.nf
.B auth-sec-servers=secondary.myisp.com	.B --auth-sec-servers=secondary.myisp.com
.fi	.fi

and	and
Line 2027 secondary to collect the DNS data. If you wish to rest	Line 2534 secondary to collect the DNS data. If you wish to rest
to particular hosts then	to particular hosts then

.nf	.nf
.B auth-peer=<IP address of secondary>	.B --auth-peer=<IP address of secondary>
.fi	.fi

will do so.	will do so.

Dnsmasq acts as an authoritative server for in-addr.arpa and	Dnsmasq acts as an authoritative server for in-addr.arpa and
ip6.arpa domains associated with the subnets given in auth-zone	ip6.arpa domains associated with the subnets given in \fB--auth-zone\fP
declarations, so reverse (address to name) lookups can be simply	declarations, so reverse (address to name) lookups can be simply
configured with a suitable NS record, for instance in this example,	configured with a suitable NS record, for instance in this example,
where we allow 1.2.3.0/24 addresses.	where we allow 1.2.3.0/24 addresses.
Line 2050 secondary servers for reverse lookups.	Line 2557 secondary servers for reverse lookups.
When dnsmasq is configured to act as an authoritative server, the	When dnsmasq is configured to act as an authoritative server, the
following data is used to populate the authoritative zone.	following data is used to populate the authoritative zone.
.PP	.PP
.B --mx-host, --srv-host, --dns-rr, --txt-record, --naptr-record	.B --mx-host, --srv-host, --dns-rr, --txt-record, --naptr-record, --caa-record,
, as long as the record names are in the authoritative domain.	as long as the record names are in the authoritative domain.
.PP	.PP
	.B --synth-domain
	as long as the domain is in the authoritative zone and, for
	reverse (PTR) queries, the address is in the relevant subnet.
	.PP
.B --cname	.B --cname
as long as the record name is in the authoritative domain. If the	as long as the record name is in the authoritative domain. If the
target of the CNAME is unqualified, then it is qualified with the	target of the CNAME is unqualified, then it is qualified with the
authoritative zone name.	authoritative zone name. CNAME used in this way (only) may be wildcards, as in

	.nf
	.B --cname=*.example.com,default.example.com
	.fi

.PP	.PP
IPv4 and IPv6 addresses from /etc/hosts (and	IPv4 and IPv6 addresses from /etc/hosts (and
.B --addn-hosts	.B --addn-hosts
Line 2064 IPv4 and IPv6 addresses from /etc/hosts (and	Line 2580 IPv4 and IPv6 addresses from /etc/hosts (and
.B --host-record	.B --host-record
and	and
.B --interface-name	.B --interface-name
	and
	.B ---dynamic-host
provided the address falls into one of the subnets specified in the	provided the address falls into one of the subnets specified in the
.B --auth-zone.	.B --auth-zone.
.PP	.PP
Addresses of DHCP leases, provided the address falls into one of the subnets specified in the	Addresses of DHCP leases, provided the address falls into one of the subnets specified in the
.B --auth-zone.	.B --auth-zone.
(If contructed DHCP ranges are is use, which depend on the address dynamically	(If constructed DHCP ranges are is use, which depend on the address dynamically
assigned to an interface, then the form of	assigned to an interface, then the form of
.B --auth-zone	.B --auth-zone
which defines subnets by the dynamic address of an interface should	which defines subnets by the dynamic address of an interface should
Line 2091 used, and must match the zone's domain.	Line 2609 used, and must match the zone's domain.


.SH EXIT CODES	.SH EXIT CODES
.PP
0 - Dnsmasq successfully forked into the background, or terminated	0 - Dnsmasq successfully forked into the background, or terminated
normally if backgrounding is not enabled.	normally if backgrounding is not enabled.
.PP	.PP
Line 2108 file/directory, permissions).	Line 2625 file/directory, permissions).
5 - Other miscellaneous problem.	5 - Other miscellaneous problem.
.PP	.PP
11 or greater - a non zero return code was received from the	11 or greater - a non zero return code was received from the
lease-script process "init" call. The exit code from dnsmasq is the	lease-script process "init" call or a
	.B \--conf-script
	file. The exit code from dnsmasq is the
script's exit code with 10 added.	script's exit code with 10 added.

.SH LIMITS	.SH LIMITS

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	Added in v.1.1.1.5