--- embedaddon/dnsmasq/man/dnsmasq.8	2013/07/29 19:37:40	1.1.1.1
+++ embedaddon/dnsmasq/man/dnsmasq.8	2023/09/27 11:02:08	1.1.1.5
@@ -1,4 +1,4 @@
-.TH DNSMASQ 8
+.TH DNSMASQ 8 2021-08-16
 .SH NAME
 dnsmasq \- A lightweight DHCP and caching DNS server.
 .SH SYNOPSIS
@@ -13,7 +13,10 @@ Dnsmasq accepts DNS queries and either answers them fr
 cache or forwards them to a real, recursive, DNS server. It loads the
 contents of /etc/hosts so that local hostnames
 which do not appear in the global DNS can be resolved and also answers
-DNS queries for DHCP configured hosts. It can also act as the authoritative DNS server for one or more domains, allowing local names to appear in the global DNS.
+DNS queries for DHCP configured hosts. It can also act as the
+authoritative DNS server for one or more domains, allowing local names
+to appear in the global DNS. It can be configured to do DNSSEC
+validation.
 .PP
 The dnsmasq DHCP server supports static address assignments and multiple
 networks. It automatically
@@ -24,10 +27,10 @@ TFTP server to allow net/PXE boot of DHCP hosts and al
 .PP
 The dnsmasq DHCPv6 server provides the same set of features as the
 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.
 .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
 Note that in general missing parameters are allowed and switch off
 functions, for instance "--pid-file" disables writing a PID file. On
@@ -39,21 +42,34 @@ the configuration file.
 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.
 .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
 Don't read the hostnames in /etc/hosts.
 .TP
 .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
-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
+.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
 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
 apply to domain names in cnames, PTR records, TXT records etc.
 .TP
 .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
 that the requester should not itself cache the information. This is
 the correct thing to do in almost all situations. This option allows a
@@ -61,6 +77,9 @@ time-to-live (in seconds) to be given for these replie
 reduce the load on the server at the expense of clients using stale
 data under some circumstances.
 .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>
 Negative replies from upstream servers normally contain time-to-live
 information in SOA records which dnsmasq uses for caching. If the
@@ -78,9 +97,25 @@ the upstream DNS servers.
 .B --max-cache-ttl=<time>
 Set a maximum TTL value for entries in the cache.
 .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>
 Set the TTL value returned in answers from the authoritative server.
 .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
 Do not go into the background at startup but otherwise run as
 normal. This is intended for use when dnsmasq is run under daemontools
@@ -92,10 +127,13 @@ don't change user id, generate a complete cache dump o
 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
 only, to stop dnsmasq daemonising in production, use 
-.B -k.
+.B --keep-in-foreground.
 .TP
 .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
 .B \-8, --log-facility=<facility>
 Set the facility to which dnsmasq will send syslog entries, this
@@ -109,6 +147,9 @@ running, will go exclusively to the file.) When loggin
 dnsmasq will close and reopen the file when it receives SIGUSR2. This 
 allows the log file to be rotated without stopping dnsmasq.
 .TP
+.B --log-debug
+Enable extra logging intended for debugging rather than information.
+.TP
 .B --log-async[=<lines>]
 Enable asynchronous logging and optionally set the limit on the
 number of lines
@@ -130,7 +171,7 @@ can be over-ridden with this switch.
 .TP
 .B \-g, --group=<groupname> 
 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.
 .TP
 .B \-v, --version
@@ -142,7 +183,8 @@ to zero completely disables DNS function, leaving only
 .TP
 .B \-P, --edns-packet-max=<size>
 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
 .B \-Q, --query-port=<query_port>
 Send outbound DNS queries from, and listen for their replies on, the
@@ -150,14 +192,29 @@ specific UDP port <query_port> instead of using random
 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
 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
+.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>
 Do not use ports less 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 to larger
-than that specified. Useful for systems behind firewalls. 
+when this option is given, the ports used will always be larger
+than that specified. Useful for systems behind firewalls. If not specified,
+defaults to 1024.
 .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>
 Listen only on the specified interface(s). Dnsmasq automatically adds
 the loopback (local) interface to the list of interfaces to use when
@@ -170,12 +227,17 @@ or
 options are given dnsmasq listens on all available interfaces except any
 given in
 .B \--except-interface
-options. IP alias interfaces (eg "eth1:0") cannot be used with
-.B --interface
+options. On Linux, when
+.B \--bind-interfaces
 or
-.B --except-interface
-options, use --listen-address instead. A simple wildcard, consisting
-of a trailing '*', can be used in 
+.B \--bind-dynamic
+are in effect, IP alias interface labels (eg "eth1:0") are checked, rather than
+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 
 and
 .B \--except-interface
@@ -189,9 +251,11 @@ and
 .B --except-interface
 options does not matter and that 
 .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
-.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
 need not be mentioned in 
 .B --interface
@@ -199,7 +263,20 @@ or 
 .B --listen-address
 configuration, indeed
 .B --auth-server
-will overide these and provide a different DNS service on the 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 the address dnsmasq is listening on.
+will override these and provide a different DNS service on the
+specified interface. The <domain> is the "glue record". It should
+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,
+it may be qualified with "/4" or "/6" to specify only the IPv4 or IPv6
+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
+.B --local-service
+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
+only has effect if there are no \fB--interface\fP, \fB--except-interface\fP,
+\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
+useful but also safe from being used for DNS amplification attacks.
 .TP 
 .B \-2, --no-dhcp-interface=<interface name>
 Do not provide DHCP or TFTP on the specified interface, but do provide DNS service.
@@ -240,14 +317,15 @@ addresses appear, it automatically listens on those (s
 access-control configuration). This makes dynamically created
 interfaces work in the same way as the default. Implementing this
 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
 .B \-y, --localise-queries
-Return answers to DNS queries from /etc/hosts which depend on the interface over which the query was
-received. If a name in /etc/hosts has more than one address associated with
+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 has more than one address associated with
 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
-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
 hosts will get the correct address based on which network they are
 attached to. Currently this facility is limited to IPv4.
@@ -255,7 +333,8 @@ attached to. Currently this facility is limited to IPv
 .B \-b, --bogus-priv
 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
-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
 .B \-V, --alias=[<old-ip>]|[<start-ip>-<end-ip>],<new-ip>[,<mask>]
 Modify IPv4 addresses returned from upstream nameservers; old-ip is
@@ -269,21 +348,34 @@ are re-written. So 
 .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
 .TP 
-.B \-B, --bogus-nxdomain=<ipaddr>
-Transform replies which contain the IP address given into "No such
-domain" replies. This is intended to counteract a devious move made by
+.B \-B, --bogus-nxdomain=<ipaddr>[/prefix]
+Transform replies which contain the specified address or subnet into "No such
+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
 an advertising web page in response to queries for unregistered names,
 instead of the correct NXDOMAIN response. This option tells dnsmasq to
 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
+.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
 .B \-f, --filterwin2k
 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
-to filter such requests. The requests blocked are for records of types SOA and SRV, and type ANY where the 
-requested name has underscores, to catch LDAP requests.
+to filter such requests. The requests blocked are for records of type ANY
+where the requested name has underscores, to catch LDAP requests, and for
+\fBall\fP records of types SOA and SRV.
 .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>
 Read the IP addresses of the upstream nameservers from <file>, instead of
 /etc/resolv.conf. For the format of this file see
@@ -306,6 +398,17 @@ been built with DBus support. If the service name is g
 provides service at that name, rather than the default which is 
 .B uk.org.thekelleys.dnsmasq
 .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
 By default, dnsmasq will send queries to any of the upstream servers
 it knows about and tries to favour servers that are known to
@@ -318,27 +421,40 @@ it will send queries to just one server. Setting this 
 dnsmasq to send all queries to all available servers. The reply from
 the server which answers first will be returned to the original requester.
 .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
 Reject (and log) addresses from upstream nameservers which are in the
-private IP ranges. This blocks an attack where a browser behind a
-firewall is used to probe machines on the local network.
+private ranges. This blocks an attack where a browser behind a
+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
 .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
 these services.
 .TP 
 .B  --rebind-domain-ok=[<domain>]|[[/<domain>/[<domain>/]
 Do not detect and block dns-rebind on queries to these domains. The
 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/
 .TP
 .B \-n, --no-poll
 Don't poll /etc/resolv.conf for changes.
 .TP
 .B --clear-on-reload
-Whenever /etc/resolv.conf is re-read, clear the DNS cache.
+Whenever /etc/resolv.conf is re-read or the upstream servers are set
+via DBus, clear the DNS cache.
 This is useful when new nameservers may have different
 data than that held in cache.
 .TP
@@ -347,37 +463,48 @@ Tells dnsmasq to never forward A or AAAA queries for p
 or domain parts, to upstream nameservers. If the name is not known
 from /etc/hosts or DHCP then a "not found" answer is returned.
 .TP
-.B \-S, --local, --server=[/[<domain>]/[domain/]][<ipaddr>[#<port>][@<source-ip>|<interface>[#<port>]]
-Specify IP address of upstream servers directly. Setting this flag does
-not suppress reading of /etc/resolv.conf, use -R to do that. If one or
-more 
+.B \-S, --local, --server=[/[<domain>]/[domain/]][<server>[#<port>]][@<interface>][@<source-ip>[#<port>]]
+Specify upstream servers directly. Setting this flag does
+not suppress reading of /etc/resolv.conf, use \fB--no-resolv\fP to do that. If one or more
 optional domains are given, that server is used only for those domains
 and they are queried only using the specified server. This is
 intended for private nameservers: if you have a nameserver on your
 network which deals with names of the form
 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
 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 // 
 has the special meaning of "unqualified names only" ie names without any
 dots in them. A non-standard port may be specified as 
 part of the IP
 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.
 
-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=/www.google.com/2.3.4.5
-will send queries for *.google.com to 1.2.3.4, except *www.google.com,
-which will go to 2.3.4.5
+will send queries for google.com and gmail.google.com to 1.2.3.4, but www.google.com
+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
 .B --server=/google.com/1.2.3.4
 .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.
 
 Also permitted is a -S
@@ -385,51 +512,120 @@ 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
 but should never forward queries on that domain to any upstream
 servers.
-.B local
+.B --local
 is a synonym for
-.B server
+.B --server
 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.
 
-The optional string after the @ character tells
-dnsmasq how to set the source of the queries to this
-nameserver. It should be an ip-address, which should belong to the machine on which
-dnsmasq is running otherwise this server line will be logged and then
-ignored, or an interface name. If an interface name is given, then
-queries to the server will be forced via that interface; if an
-ip-address is given then the source address of the queries will be set
-to that address.
+The optional string after the @ character tells dnsmasq how to set the source of
+the queries to this nameserver. It can either be an ip-address, an interface
+name or both. The ip-address should belong to the machine on which dnsmasq is
+running, otherwise this server line will be logged and then ignored. If an
+interface name is given, then queries to the server will be forced via that
+interface; if an ip-address is given then the source address of the queries will
+be set to that address; and if both are given then a combination of ip-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
 source address specified but the port may be specified directly as
 part of the source address. Forcing queries to an interface is not
 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
-.B \-A, --address=/<domain>/[domain/]<ipaddr>
+.B --rev-server=<ip-address>[/<prefix-len>][,<server>][#<port>][@<interface>][@<source-ip>[#<port>]]
+This is functionally the same as 
+.B --server, 
+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
+is exactly equivalent to 
+.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
+.B \-A, --address=/<domain>[/<domain>...]/[<ipaddr>]
 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
-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
 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 specification works in the same was as for --server, with the
-additional facility that /#/ matches any domain. Thus
---address=/#/1.2.3.4 will always return 1.2.3.4 for any query not
-answered from /etc/hosts or DHCP and not sent to an upstream
-nameserver by a more specific --server directive.
+domain specification works in the same way as for \fB--server\fP, with
+the additional facility that \fB/#/\fP matches any domain. Thus
+\fB--address=/#/1.2.3.4\fP will always return \fB1.2.3.4\fP for any
+query not answered from \fB/etc/hosts\fP or DHCP and not sent to an
+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
-.B --ipset=/<domain>/[domain/]<ipset>[,<ipset>]
-Places the resolved IP addresses of queries for the specified domains
-in the specified netfilter ip sets. Domains and subdomains are matched
-in the same way as --address. These ip sets must already exist. See
-ipset(8) for more details.
+.B --ipset=/<domain>[/<domain>...]/<ipset>[,<ipset>...]
+Places the resolved IP addresses of queries for one or more domains in
+the specified Netfilter IP set. If multiple setnames are given, then the
+addresses are placed in each of them, subject to the limitations of an
+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
+.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>]
 Return an MX record named <mx name> pointing to the given hostname (if
 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 
 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
@@ -437,7 +633,7 @@ to a central server. The preference value is optional,
 .TP 
 .B \-t, --mx-target=<hostname>
 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 
 hostname of the machine on which dnsmasq is running.
 .TP
@@ -446,7 +642,7 @@ Return an MX record pointing to itself for each local
 machine. Local machines are those in /etc/hosts or with DHCP leases.
 .TP 
 .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
 local machine. Local machines are those in /etc/hosts or with DHCP
 leases.
@@ -462,24 +658,34 @@ zone files: the port, weight and priority numbers are 
 order. More than one SRV record for a given service/domain is allowed,
 all that match are returned.
 .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
 the DNS with associated IPv4 (A) and IPv6 (AAAA) records. A name may
 appear in more than one 
-.B host-record
+.B --host-record
 and therefore be assigned more than one address. Only the first
 address creates a PTR record linking the address to the name. This is
 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
 appearing there inhibits PTR-record creation if it appears in
 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 
-.B host-record,
+.B --host-record,
 eg. 
 .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
+.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>]
 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
@@ -492,15 +698,21 @@ Return a PTR DNS record.
 .B --naptr-record=<name>,<order>,<preference>,<flags>,<service>,<regexp>[,<replacement>]
 Return an NAPTR DNS record, as specified in RFC3403.
 .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
-<target>. There are significant limitations on the target; it must be a
-DNS name which is known to dnsmasq from /etc/hosts (or additional
-hosts files), from DHCP or from another 
-.B --cname.
-If the target does not satisfy this
-criteria, the whole cname is ignored. The cname must be unique, but it
-is permissable to have more than one cname pointing to the same target.
+<target>. There is a significant limitation on the target; it must be a
+DNS record which is known to dnsmasq and NOT a DNS record which comes from
+an upstream server. The cname must be unique, but it
+is permissible to have more than one cname pointing to the same target. Indeed
+it's possible to declare multiple cnames to a target in a single line, like so:
+.B --cname=cname1,cname2,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
 .B --dns-rr=<name>,<RR-number>,[<hex data>]
 Return an arbitrary DNS Resource Record. The number is the type of the
@@ -508,61 +720,229 @@ record (which is always in the C_IN class). The value 
 given by the hex data, which may be of the form 01:23:45 or 01 23 45 or
 012345 or any mixture of these.
 .TP
-.B --interface-name=<name>,<interface>
-Return a DNS record associating the name with the primary address on
-the given interface. This flag specifies an A record for the given
+.B --interface-name=<name>,<interface>[/4|/6]
+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
 name in the same way as an /etc/hosts line, except that the address is
-not constant, but taken from the given interface. If the interface is
+not constant, but taken from the given interface. The interface may be
+followed by "/4" or "/6" to specify that only IPv4 or IPv6 addresses
+of the interface should be used. If the interface is
 down, not configured or non-existent, an empty record is returned. The
 matching PTR record is also created, mapping the interface address to
 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
-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
-.B --add-mac
+.B --synth-domain=<domain>,<address range>[,<prefix>[*]]
+Create artificial A/AAAA and PTR records for an address range. The
+records either seqential numbers or the address, with periods (or colons for IPv6) replaced with dashes.
+
+An examples should make this clearer. First sequential numbers.
+.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
+192.168.0.56 and a reverse query vice versa. The same applies to IPv6,
+but IPv6 addresses may start with '::'
+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.
+
+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
+<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
+.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
 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
 subnet as the dnsmasq server. Note that the mechanism used to achieve this (an EDNS0 option)
 is not yet standardised, so this should be considered
 experimental. Also note that exposing MAC addresses in this way may
-have security and privacy implications. 
+have security and privacy implications. The warning about caching
+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 
+.B --add-subnet[[=[<IPv4 address>/]<IPv4 prefix length>][,[<IPv6 address>/]<IPv6 prefix length>]]
+Add a subnet address to the DNS queries which are forwarded
+upstream. If an address is specified in the flag, it will be used,
+otherwise, the address of the requestor will be used. The amount of
+the address forwarded depends on the prefix length parameter: 32 (128
+for IPv6) forwards the whole address, zero forwards none of it but
+still marks the request so that no upstream nameserver will add client
+address information either. The default is zero for both IPv4 and
+IPv6. Note that upstream nameservers may be configured to return
+different results based on this information, but the dnsmasq cache
+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
+.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>
-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
 .B \-N, --no-negcache
 Disable negative caching. Negative caching allows dnsmasq to remember
 "no such domain" answers from upstream nameservers and answer
 identical queries without forwarding them again. 
 .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>
 Set the maximum number of concurrent DNS queries. The default value is
 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
-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
+.B --dnssec
+Validate DNS replies and cache DNSSEC data. When forwarding DNS queries, dnsmasq requests the 
+DNSSEC records needed to validate the replies. The replies are validated and the result returned as 
+the Authenticated Data bit in the DNS packet. In addition the DNSSEC records are stored in the cache, making 
+validation by clients more efficient. Note that validation by clients is the most secure DNSSEC mode, but for
+clients unable to do validation, use of the AD bit set by dnsmasq is useful, provided that the network between 
+the dnsmasq server and the client is trusted. Dnsmasq must be compiled with HAVE_DNSSEC enabled, and DNSSEC
+trust anchors provided, see 
+.B --trust-anchor.
+Because the DNSSEC validation process uses the cache, it is not
+permitted to reduce the cache size below the default when DNSSEC is
+enabled. The nameservers upstream of dnsmasq must be DNSSEC-capable,
+ie capable of returning DNSSEC records with data. If they are not,
+then dnsmasq will not be able to determine the trusted status of
+answers and this means that DNS service will be entirely broken.
+.TP
+.B --trust-anchor=[<class>],<domain>,<key-tag>,<algorithm>,<digest-type>,<digest>
+Provide DS records to act a trust anchors for DNSSEC
+validation. Typically these will be the DS record(s) for Key Signing
+key(s) (KSK) of the root zone,
+but trust anchors for limited domains are also possible. The current
+root-zone trust anchors may be downloaded from https://data.iana.org/root-anchors/root-anchors.xml 
+.TP
+.B --dnssec-check-unsigned[=no]
+As a default, dnsmasq checks that unsigned DNS replies are
+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
+attacker forging unsigned replies for signed DNS zones, but it is
+fast.
+
+Versions of dnsmasq prior to 2.80 defaulted to not checking unsigned replies, and used 
+.B --dnssec-check-unsigned
+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.
+.TP
+.B --dnssec-no-timecheck
+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 
+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 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 
+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 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
+.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
-A resolver on a client machine can do DNSSEC validation in two ways: it
-can perform the cryptograhic operations on the reply it receives, or
-it can rely on the upstream recursive nameserver to do the validation
-and set a bit in the reply if it succeeds. Dnsmasq is not a DNSSEC
-validator, so it cannot perform the validation role of the recursive nameserver,
-but it can pass through the validation results from its own upstream
-nameservers. This option enables this behaviour. You should only do
-this if you trust all the configured upstream nameservers 
-.I and the network between you and them.
-If you use the first DNSSEC mode, validating resolvers in clients,
-this option is not required. Dnsmasq always returns all the data
-needed for a client to do validation itself. 
+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 
+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
-.B --auth-zone=<domain>[,<subnet>[,<subnet>.....]]
+.B --dnssec-debug
+Set debugging mode for the DNSSEC validation, set the Checking Disabled bit on upstream queries, 
+and don't convert replies which do not validate to responses with
+a return code of SERVFAIL. Note that
+setting this may affect DNS behaviour in bad ways, it is not an
+extra-logging flag and should not be set in production.
+.TP
+.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
-will be served, except that A and AAAA records must be in one of the
-specified subnets, or in a subnet corresponding to a contructed DHCP
-range. The subnet(s) are also used to define in-addr.arpa and
-ipv6.arpa domains which are served for reverse-DNS queries. For IPv4
-subnets, the prefix length is limited to the values 8, 16 or 24.
+will be served. If subnet(s) are given, A and AAAA records must be in one of the
+specified subnets.
+
+As alternative to directly specifying the subnets, it's possible to
+give the name of an interface, in which case the subnets implied by
+that interface's configured addresses and netmask/prefix-length are
+used; this is useful when using constructed DHCP ranges as the actual
+address is dynamic and not known when configuring dnsmasq. The
+interface addresses may be confined to only IPv6 addresses using
+<interface>/6 or to only IPv4 using <interface>/4. This is useful when
+an interface has dynamically determined global IPv6 addresses which should
+appear in the zone, but RFC1918 IPv4 addresses which should not.
+Interface-name and address-literal subnet specifications may be used
+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
+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.
+For IPv4 subnets, the prefix length should be have the value 8, 16 or 24
+unless you are familiar with RFC 2317 and have arranged the
+in-addr.arpa delegation accordingly. Note that if no subnets are
+specified, then no reverse queries are answered.
 .TP
 .B --auth-soa=<serial>[,<hostmaster>[,<refresh>[,<retry>[,<expiry>]]]]
 Specify fields in the SOA record associated with authoritative
@@ -577,8 +957,13 @@ authoritative zones as dnsmasq.
 .B --auth-peer=<ip-address>[,<ip-address>[,<ip-address>...]]
 Specify the addresses of secondary servers which are allowed to
 initiate zone transfer (AXFR) requests for zones for which dnsmasq is
-authoritative. If this option is not given, then AXFR requests will be
-accepted from any secondary. 
+authoritative. If this option is not given but --auth-sec-servers is,
+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 
 .B --conntrack
 Read the Linux connection track mark associated with incoming DNS
@@ -588,20 +973,20 @@ associated with the queries which cause it, useful for
 accounting and firewalling. Dnsmasq must have conntrack support
 compiled in and the kernel must have conntrack support
 included and configured. This option cannot be combined with
---query-port. 
+.B --query-port.
 .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
 .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
 <start-addr> to <end-addr> and from statically defined addresses given
 in 
-.B dhcp-host
+.B --dhcp-host
 options. If the lease time is given, then leases
 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,
-the default lease time is one hour. The
+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 for IPv4 and one day for IPv6. The
 minimum lease time is two minutes. For IPv6 ranges, the lease time
 maybe "deprecated"; this sets the preferred lifetime sent in a DHCP
 lease or router advertisement to zero, which causes clients to use
@@ -616,12 +1001,13 @@ agent, dnsmasq cannot determine the netmask itself, so
 specified, otherwise dnsmasq will have to guess, based on the class (A, B or
 C) of the network address. The broadcast address is
 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
-and broadcast address, there is an optional prefix length. If not
+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
 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.
 
 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
@@ -630,12 +1016,25 @@ This forms a template which describes how to create ra
 
 .B --dhcp-range=::1,::400,constructor:eth0
 
-will look for addresses of the form <network>::1 on eth0 and then create a range from <network>::1 to <network>::400. If the interface is assigned more than one network, then the corresponding ranges will be automatically created, and then deprecated and finally removed again as the address is deprecated and then deleted. The interface name may have a final "*" wildcard.
+will look for addresses on
+eth0 and then create a range from <network>::1 to <network>::400. If
+the interface is assigned more than one network, then the
+corresponding ranges will be automatically created, and then
+deprecated and finally removed again as the address is deprecated and
+then deleted. The interface name may have a final "*" wildcard. Note
+that just any address on eth0 will not do: it must not be an
+autoconfigured or privacy address, or be deprecated.
 
+If a \fB--dhcp-range\fP is only being used for stateless DHCP and/or SLAAC,
+then the address can be simply ::
+
+.B --dhcp-range=::,constructor:eth0
+
+
 The optional 
 .B set:<tag> 
 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
 a tag to matching it. Only one tag may be set, but more than one tag
 may be matched.
@@ -645,24 +1044,24 @@ The optional <mode> keyword may be 
 which tells dnsmasq to enable DHCP for the network specified, but not
 to dynamically allocate IP addresses: only hosts which have static
 addresses given via 
-.B dhcp-host
+.B --dhcp-host
 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
 Information-request packets on a subnet which is provided with
 stateless DHCPv6, ie
-.B --dhcp=range=::,static
+.B --dhcp-range=::,static
 
 For IPv4, the <mode> may be 
 .B proxy
 in which case dnsmasq will provide proxy-DHCP on the specified
 subnet. (See 
-.B pxe-prompt
+.B --pxe-prompt
 and 
-.B pxe-service
+.B --pxe-service
 for details.)
 
 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
 tells dnsmasq to offer Router Advertisement only on this subnet,
@@ -697,8 +1096,16 @@ can be combined  with 
 and
 .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
-.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
 with a particular hardware address to be always allocated the same
 hostname, IP address and lease time. A hostname specified like this
@@ -716,12 +1123,13 @@ dnsmasq to always allocate the machine lap the IP addr
 192.168.0.199. 
 
 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
 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 rather than
+It is allowed to use client identifiers (called client
+DUID in IPv6-land) rather than
 hardware addresses to identify hosts by prefixing with 'id:'. Thus: 
 .B --dhcp-host=id:01:02:03:04,..... 
 refers to the host with client identifier 01:02:03:04. It is also
@@ -729,18 +1137,26 @@ allowed to specify the client ID as text, like this:
 .B --dhcp-host=id:clientidastext,..... 
 
 A single
-.B dhcp-host 
-may contain an IPv4 address or an IPv6 address, or both. IPv6 addresses must be bracketed by square brackets thus:
+.B --dhcp-host
+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]
 IPv6 addresses may contain only the host-identifier part:
 .B --dhcp-host=laptop,[::56]
-in which case they act as wildcards in constructed dhcp ranges, with
-the appropriate network part inserted. 
-Note that in IPv6 DHCP, the hardware address is not normally
-available, so a client must be identified by client-id (called client
-DUID in IPv6-land) or hostname. 
+in which case they act as wildcards in constructed DHCP ranges, with
+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.
 
-The special option id:* means "ignore any client-id 
+Note that in IPv6 DHCP, the hardware address may not be
+available, though it normally is for direct-connected clients, or
+clients using DHCP relays which support RFC 6939.
+
+
+For DHCPv4, the  special option id:* means "ignore any client-id 
 and use MAC addresses only." This is useful when a client presents a client-id sometimes 
 but not others.
 
@@ -749,11 +1165,25 @@ allocated to a DHCP lease, but only if a 
 .B --dhcp-host
 option specifying the name also exists. Only one hostname can be
 given in a 
-.B dhcp-host
+.B --dhcp-host
 option, but aliases are possible by using CNAMEs. (See 
 .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"
 tells dnsmasq to never offer a DHCP lease to a machine. The machine
 can be specified by hardware address, client ID or hostname, for
@@ -763,15 +1193,23 @@ This is
 useful when there is another DHCP server on the network which should
 be used by some machines.
 
-The set:<tag> contruct sets the tag
-whenever this dhcp-host directive is in use. This can be used to 
+The set:<tag> construct sets the tag
+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
-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
-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
 ignore requests from unknown machines using
 .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
 wildcard bytes, so for example 
 .B --dhcp-host=00:20:e0:3b:13:*,ignore 
@@ -801,22 +1239,34 @@ has both wired and wireless interfaces.
 .TP
 .B --dhcp-hostsfile=<path>
 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
-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:
 the file will be re-read when dnsmasq receives SIGHUP.
 .TP
 .B --dhcp-optsfile=<path>
 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 
-using this option is the same as for --dhcp-hostsfile: the
-dhcp-optsfile will be re-read when dnsmasq receives SIGHUP. Note that
+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 \fB--dhcp-hostsfile\fP: the
+\fB--dhcp-optsfile\fP will be re-read when dnsmasq receives SIGHUP. Note that
 it is possible to encode the information in a
 .B --dhcp-boot
 flag as DHCP options, using the options names bootfile-name,
 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 
 .B \-Z, --read-ethers
 Read /etc/ethers for information about hosts for the DHCP server. The
@@ -847,9 +1297,19 @@ and to set the time-server address to 192.168.0.4, do
 .B --dhcp-option = 42,192.168.0.4 
 or 
 .B --dhcp-option = option:ntp-server, 192.168.0.4
-The special address 0.0.0.0 (or [::] for DHCPv6) is taken to mean "the address of the
-machine running dnsmasq". Data types allowed are comma separated
-dotted-quad IP addresses, a decimal number, colon-separated hex digits
+The special address 0.0.0.0 is taken to mean "the address of the
+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
+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
 this option is only sent when all the tags are matched.
 
@@ -865,7 +1325,9 @@ keyword, followed by the option number or option name.
 name space is disjoint from the IPv4 option name space. IPv6 addresses
 in options must be bracketed with square brackets, eg. 
 .B --dhcp-option=option6:ntp-server,[1234::56]
- 
+For IPv6, [::] means "the global address of
+the machine running dnsmasq", whilst [fd00::] is replaced with the
+ULA, if it exists, and [fe80::] with the link-local address.
 
 Be careful: no checking is done that the correct type of data for the
 option number is sent, it is quite possible to
@@ -883,12 +1345,12 @@ a literal IP address as TFTP server name, it is necess
 .B --dhcp-option=66,"1.2.3.4"
 
 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 
 sends the encapsulated vendor
 class-specific option "mftp-address=0.0.0.0" to any client whose
 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 
 for selecting encapsulated options in preference to any sent by the
 client. It is
@@ -901,7 +1363,7 @@ Options may be encapsulated (IPv4 only) within other o
 will send option 175, within which is the option 190. If multiple
 options are given which are encapsulated with the same option number
 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
 Vendor Options" as specified by RFC3925. These are denoted like this: 
@@ -923,17 +1385,56 @@ needed, for example when sending options to PXELinux.
 .B --dhcp-no-override
 (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
-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
 options but can, rarely, confuse old or broken clients. This flag
 forces "simple and safe" behaviour to avoid problems in such a case.
 .TP
+.B --dhcp-relay=<local address>[,<server address>[#<server port>]][,<interface]
+Configure dnsmasq to do DHCP relay. The local address is an address
+allocated to an interface on the host running dnsmasq. All 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
+address to multiple remote servers by using multiple \fB--dhcp-relay\fP
+configs with the same local address and different server
+addresses. A server address must be an IP literal address, not a
+domain name. If the server address is omitted, the request will be
+forwarded by broadcast (IPv4) or multicast (IPv6). In this case the interface
+must be given and not be wildcard. The server address may specify a non-standard
+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
+server, see \fB--interface\fP, \fB--except-interface\fP, etc. The optional
+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
+accepted. This is intended for configurations which have three
+interfaces: one being relayed from, a second connecting the DHCP
+server, and a third untrusted network, typically the wider
+internet. It avoids the possibility of spoof replies arriving via this
+third interface.
+
+It is allowed to have dnsmasq act as a DHCP server on one set of
+interfaces and relay from a disjoint set of interfaces. Note that
+whilst it is quite possible to write configurations which appear to
+act as a server and a relay on the same interface, this is not
+supported: the relay function will take precedence.
+
+Both DHCPv4 and DHCPv6 relay is supported. It's not possible to relay
+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
 .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 
 "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
 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:
 .B --dhcp-option=tag:printers,3,192.168.4.4 
 The vendor-class string is
@@ -956,7 +1457,7 @@ this to set a different printer server for hosts in th
 "accounts" than for hosts in the class "engineering".
 .TP
 .B \-4, --dhcp-mac=set:<tag>,<MAC address>
-(IPv4 only) Map from a MAC address to a tag. The MAC address may include
+Map from a MAC address to a tag. The MAC address may include
 wildcards. For example
 .B --dhcp-mac=set:3com,01:34:23:*:*:*
 will set the tag "3com" for any host whose MAC address matches the pattern.
@@ -968,8 +1469,8 @@ normally given as colon-separated hex, but is also all
 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. 
 
-.B dhcp-remoteid
-(but not dhcp-circuitid) is supported in IPv6. 
+.B --dhcp-remoteid
+(but not \fB--dhcp-circuitid\fP) is supported in IPv6.
 .TP
 .B --dhcp-subscrid=set:<tag>,<subscriber-id>
 (IPv4 and IPv6) Map from RFC3993 subscriber-id relay agent options to tags.
@@ -978,11 +1479,11 @@ agent ID and one provided by a relay agent, the tag is
 (IPv4 only) A normal DHCP relay agent is only used to forward the initial parts of
 a DHCP interaction to the DHCP server. Once a client is configured, it
 communicates directly with the server. This is undesirable if the
-relay agent is addding extra information to the DHCP packets, such as
+relay agent is adding extra information to the DHCP packets, such as
 that used by
-.B dhcp-circuitid
+.B --dhcp-circuitid
 and
-.B dhcp-remoteid.
+.B --dhcp-remoteid.
 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
 packets passing through it. This flag provides an alternative method
@@ -995,32 +1496,39 @@ relays at those addresses are affected.
 Without a value, set the tag if the client sends a DHCP
 option of the given number or name. When a value is given, set the tag only if
 the option is sent and matches the value. The value may be of the form
-"01:ff:*:02" in which case the value must match (apart from widcards)
+"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
 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
 must match, so
-
---dhcp-match=set:efi-ia32,option:client-arch,6
-
+.B --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
 architectures sent by the client in option 93. (See RFC 4578 for
 details.)  If the value is a string, substring matching is used.
 
-The special form with vi-encap:<enterpise number> matches against
+The special form with vi-encap:<enterprise number> matches against
 vendor-identifying vendor classes for the specified enterprise. Please
 see RFC 3925 for more details of these rare and interesting beasts.
 .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>]]]
 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)
 If no tag:<tag> appears set:<tag> tags are set unconditionally.
 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
-.B tag-if,
+.B --tag-if,
 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
 .B \-J, --dhcp-ignore=tag:<tag>[,tag:<tag>]
 When all the given tags appear in the tag set ignore the host and do
@@ -1028,15 +1536,15 @@ not allocate it a DHCP lease.
 .TP
 .B --dhcp-ignore-names[=tag:<tag>[,tag:<tag>]]
 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
 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.
 .TP
 .B --dhcp-generate-names=tag:<tag>[,tag:<tag>]
 (IPv4 only) Generate a name for DHCP clients which do not otherwise have one,
-using the MAC address expressed in hex, seperated by dashes. Note that
+using the MAC address expressed in hex, separated by dashes. Note that
 if a host provides a name, it will be used by preference to this,
 unless 
 .B --dhcp-ignore-names 
@@ -1076,27 +1584,34 @@ address, and setting this flag enables this mode. Note
 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.
 .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>]
 Most uses of PXE boot-ROMS simply allow the PXE
 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
 functions when supported by a suitable DHCP server.
 
 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
 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
 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,
 either from itself (
-.B enable-tftp 
+.B --enable-tftp
 must be set for this to work) or another TFTP server if the final server
 address/name is given.
 Note that the "layer"
-suffix (normally ".0") is supplied by PXE, and should not be added to
-the basename. If an integer boot service type, rather than a basename
+suffix (normally ".0") is supplied by PXE, and need not be added to
+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
 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.  
@@ -1112,23 +1627,38 @@ timeout is given then after the
 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
 item will be executed immediately. If 
-.B pxe-prompt
-is ommitted the system will wait for user input if there are multiple
+.B --pxe-prompt
+is omitted the system will wait for user input if there are multiple
 items in the menu, but boot immediately if
 there is only one. See
-.B pxe-service 
+.B --pxe-service
 for details of menu items.
 
 Dnsmasq supports PXE "proxy-DHCP", in this case another DHCP server on
 the network is responsible for allocating IP addresses, and dnsmasq
 simply provides the information given in 
-.B pxe-prompt
+.B --pxe-prompt
 and
-.B pxe-service
+.B --pxe-service
 to allow netbooting. This mode is enabled using the
 .B proxy
 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  
 .B \-X, --dhcp-lease-max=<number>
 Limits dnsmasq to the specified maximum number of DHCP leases. The
@@ -1145,6 +1675,13 @@ allows dnsmasq to rebuild its lease database without e
 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).
 .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>]]
 (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
@@ -1162,7 +1699,7 @@ enables dynamic allocation. With tags, only when the t
 set. It may be repeated with different tag sets. 
 .TP
 .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
 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
@@ -1172,6 +1709,12 @@ tried. This flag disables this check. Use with caution
 Extra logging for DHCP: log all the options sent to DHCP clients and
 the tags used to determine them.
 .TP
+.B --quiet-dhcp, --quiet-dhcp6, --quiet-ra, --quiet-tftp
+Suppress logging of the routine operation of these protocols. Errors and
+problems will still be logged. \fB--quiet-tftp\fP does not consider file not
+found to be an error. \fB--quiet-dhcp\fP and quiet-dhcp6 are over-ridden by
+\fB--log-dhcp\fP.
+.TP
 .B \-l, --dhcp-leasefile=<path>
 Use the specified file to store DHCP lease information.
 .TP 
@@ -1182,7 +1725,7 @@ DUID automatically when it is first needed. When given
 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
 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.
 .TP
 .B \-6 --dhcp-script=<path>
@@ -1196,7 +1739,8 @@ address of the host (or DUID for IPv6) , the IP addres
 if known. "add" means a lease has been created, "del" means it has
 been destroyed, "old" is a notification of an existing lease when
 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,
 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
@@ -1219,8 +1763,14 @@ If dnsmasq was compiled with HAVE_BROKEN_RTC, then
 the length of the lease (in seconds) 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
-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
 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 
@@ -1241,6 +1791,11 @@ DNSMASQ_LOG_DHCP is set if
 .B --log-dhcp
 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:
 
 DNSMASQ_CLIENT_ID if the host provided a client-id.
@@ -1262,8 +1817,8 @@ every call to the script.
 DNSMASQ_IAID containing the IAID for the lease. If the lease is a
 temporary allocation, this is prefixed to 'T'.
 
+DNSMASQ_MAC containing the MAC address of the client, if known.
 
-
 Note that the supplied hostname, vendorclass and userclass data is
 only  supplied for
 "add" actions or "old" actions when a host resumes an existing lease,
@@ -1273,8 +1828,8 @@ database.
 
 
 All file descriptors are
-closed except stdin, stdout and stderr which are open to /dev/null
-(except in debug mode).
+closed except stdin, which is open to /dev/null, and stdout and stderr which capture output for logging by dnsmasq. 
+(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
 of the script is ever running (dnsmasq waits for an instance of script to exit
@@ -1289,23 +1844,38 @@ At dnsmasq startup, the script will be invoked for
 all existing leases as they are read from the lease file. Expired
 leases will be called with "del" and others with "old". When dnsmasq
 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
-to the script, "init" and "tftp". More may be added in the future, so
+There are five further actions which may appear as the first argument
+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
 described below in 
 .B --leasefile-ro
+
 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
 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
 .B --dhcp-luascript=<path>
 Specify a script written in Lua, to be run when leases are created,
 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
 events. The Lua code must define a
 .B lease
@@ -1347,10 +1917,24 @@ table holds the tags 
 .B file_name
 and 
 .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
 .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. 
-.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
 Completely suppress use of the lease database file. The file will not
 be created, read, or written. Change the way the lease-change
@@ -1365,20 +1949,61 @@ stdout and exit with zero exit code. Setting this
 option also forces the leasechange script to be called on changes
 to the client-id and lease length and expiry time.
 .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>]
-Treat DHCP request packets arriving at any of the <alias> interfaces
-as if they had arrived at <interface>. This option is necessary when
-using "old style" bridging on BSD platforms, since
-packets arrive at tap interfaces which don't have an IP address.
+Treat DHCP (v4 and v6) requests and IPv6 Router Solicit packets
+arriving at any of the <alias> interfaces as if they had arrived at
+<interface>.  This option allows dnsmasq to provide DHCP and RA
+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
-.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 
 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
 which request it, and secondly it sets the domain which it is legal
 for DHCP-configured hosts to claim. The intention is to constrain
 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
 hostname with a domain part (ie with a period) will be disallowed 
 and logged. If suffix is specified, then hostnames with a domain 
@@ -1400,19 +2025,23 @@ which can change the behaviour of dnsmasq with domains
 
 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
---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
 is identical to
 .B --domain=thekelleys.org.uk,192.168.0.0/24
---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.
+.B --local=/thekelleys.org.uk/ --local=/0.168.192.in-addr.arpa/
+
+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
 .B --dhcp-fqdn
 In the default mode, dnsmasq inserts the unqualified names of
 DHCP clients into the DNS. For this reason, the names must be unique,
 even if two clients which have the same name are in different
 domains. If a second DHCP client appears which has the same name as an
-existing client, the name is transfered to the new client. If 
+existing client, the name is transferred to the new client. If 
 .B --dhcp-fqdn
 is set, this behaviour changes: the unqualified name is no longer
 put in the DNS, only the qualified name. Two DHCP clients with the
@@ -1439,22 +2068,47 @@ discovery and (possibly) prefix discovery for autonomo
 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
 existing DHCP configuration to provide most data. When RA is enabled,
-dnsmasq will advertise a prefix for each dhcp-range, with default
-router and recursive DNS server as the relevant link-local address on 
-the machine running dnsmasq. By default, he "managed address" bits are set, and
+dnsmasq will advertise a prefix for each \fB--dhcp-range\fP, with default
+router  as the relevant link-local address on 
+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
 subnets with the mode keywords described in
 .B --dhcp-range.
 RFC6106 DNS parameters are included in the advertisements. By default,
 the relevant link-local address of the machine running dnsmasq is sent
 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
-.B --enable-tftp
+.B --ra-param=<interface>,[mtu:<integer>|<interface>|off,][high,|low,]<ra-interval>[,<router lifetime>]
+Set non-default values for router advertisements sent via an
+interface. The priority field for the router may be altered from the
+default of medium with eg
+.B --ra-param=eth0,high.
+The interval between router advertisements may be set (in seconds) with 
+.B --ra-param=eth0,60.
+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. 
+.B --ra-param=eth0,0,0
+(A value of zero for the interval means the default value.) All four parameters may be set at once.
+.B --ra-param=eth0,mtu:1280,low,60,1200
+
+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
+.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>]]
 Enable the TFTP server function. This is deliberately limited to that
 needed to net-boot a client. Only reading is allowed; the tsize and
 blksize extensions are supported (tsize is only supported in octet
-mode). 
+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 receive TFTP service.
 .TP
 .B --tftp-root=<directory>[,<interface>]
 Look for files to transfer using TFTP relative to the given
@@ -1464,22 +2118,29 @@ Absolute paths (starting with /) are allowed, but they
 the tftp-root. If the optional interface argument is given, the
 directory is only used for TFTP requests via that interface.
 .TP
-.B --tftp-unique-root
-Add the IP address of the TFTP client as a path component on the end
-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.
+.B --tftp-no-fail
+Do not abort startup if specified tftp root directories are inaccessible.
 .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
 Enable TFTP secure mode: without this, any file which is readable by
 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
-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
 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. 
 .TP
 .B --tftp-lowercase
@@ -1500,6 +2161,10 @@ require about (2*n) + 10 descriptors. If 
 .B --tftp-port-range
 is given, that can affect the number of concurrent connections.
 .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
 Stop the TFTP server from negotiating the "blocksize" option with a
 client. Some buggy clients request this option but then behave badly
@@ -1513,18 +2178,66 @@ specifies a range of ports for use by TFTP transfers. 
 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
 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>
-Specify a different configuration file. The conf-file option is also allowed in
-configuration files, to include multiple configuration files. A
+Specify a configuration file. The presence of this option stops dnsmasq from reading the default configuration
+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.
 .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
 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
-with # are always skipped. This flag may be given on the command
-line or in a configuration file.
+with # are always skipped. If the extension starts with * then only files 
+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
+.B --servers-file=<file>
+A special case of 
+.B --conf-file
+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
+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
 At startup, dnsmasq reads
 .I /etc/dnsmasq.conf,
@@ -1532,9 +2245,9 @@ if it exists. (On
 FreeBSD, the file is 
 .I /usr/local/etc/dnsmasq.conf
 ) (but see the 
-.B \-C
+.B \--conf-file
 and
-.B \-7
+.B \--conf-dir
 options.) The format of this
 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
@@ -1550,8 +2263,9 @@ clears its cache and then re-loads 
 .I /etc/hosts
 and 
 .I /etc/ethers 
-and any file given by --dhcp-hostsfile, --dhcp-optsfile or --addn-hosts.
-The dhcp lease change script is called for all
+and any file given by \fB--dhcp-hostsfile\fP, \fB--dhcp-hostsdir\fP, \fB--dhcp-optsfile\fP,
+\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 
 .B
 --no-poll
@@ -1565,13 +2279,14 @@ When it receives a SIGUSR1,
 writes statistics to the system log. It writes the cache size,
 the number of names which have had to removed from the cache before
 they expired in order to make room for new names and the total number
-of names that have been inserted into the cache. For each upstream
+of names that have been inserted into the cache. The number of cache hits and 
+misses and the number of authoritative queries answered are also given. For each upstream
 server it gives the number of queries sent, and the number which
 resulted in an error. In 
 .B --no-daemon
-mode or when full logging is enabled (-q), a complete dump of the
-contents of the cache is made.
-.PP 
+mode or when full logging is enabled (\fB--log-queries\fP), a complete dump of the
+contents of the cache is made. 
+
 When it receives SIGUSR2 and it is logging direct to a file (see
 .B --log-facility
 ) 
@@ -1593,7 +2308,7 @@ and
 
  
 .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
 forwards such queries to a fully recursive upstream DNS server which is
 typically provided by an ISP. By default, dnsmasq reads
@@ -1641,7 +2356,7 @@ using 
 options or put their addresses real in another file, say
 .I /etc/resolv.dnsmasq
 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
 addresses by PPP or DHCP.
 .PP
@@ -1659,67 +2374,66 @@ the CNAME is shadowed too.
 The tag system works as follows: For each DHCP request, dnsmasq
 collects a set of valid tags from active configuration lines which
 include set:<tag>, including one from the 
-.B dhcp-range
+.B --dhcp-range
 used to allocate the address, one from any matching 
-.B dhcp-host
-(and "known" if a dhcp-host matches) 
+.B --dhcp-host
+(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 
 name of the interface on which the request arrived is also set.
 
-Any configuration lines which includes one or more tag:<tag> contructs
+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
-above. Typically this is dhcp-option.
-.B dhcp-option 
+above. Typically this is \fB--dhcp-option\fP.
+.B --dhcp-option
 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
 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
 command line rather than a configuration file, be sure to escape !,
 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
 individual hosts, so 
-.B dhcp-range=set:interface1,......
-.B dhcp-host=set:myhost,.....
-.B dhcp-option=tag:interface1,option:nis-domain,"domain1"
-.B dhcp-option=tag:myhost,option:nis-domain,"domain2"
+.B --dhcp-range=set:interface1,......
+.B --dhcp-host=set:myhost,.....
+.B --dhcp-option=tag:interface1,option:nis-domain,"domain1"
+.B --dhcp-option=tag:myhost,option:nis-domain,"domain2"
 will set the NIS-domain to domain1 for hosts in the range, but
 override that to domain2 for a particular host.
 
 .PP
 Note that for 
-.B dhcp-range 
+.B --dhcp-range
 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.
 
 This system evolved from an earlier, more limited one and for backward
 compatibility "net:" may be used instead of "tag:" and "set:" may be
 omitted. (Except in 
-.B dhcp-host,
+.B --dhcp-host,
 where "net:" may be used instead of "set:".) For the same reason, '#'
 may be used instead of '!' to indicate NOT.
 .PP 
 The DHCP server in dnsmasq will function as a BOOTP server also,
 provided that the MAC address and IP address for clients are given,
 either using 
-.B dhcp-host 
+.B --dhcp-host
 configurations or in
 .I /etc/ethers
 , and a
-.B dhcp-range 
+.B --dhcp-range
 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
 parameter in a BOOTP request is used as a tag,
 as is the tag "bootp", allowing some control over the options returned to
 different classes of hosts.
 
 .SH AUTHORITATIVE CONFIGURATION
-.PP 
 Configuring dnsmasq to act as an authoritative DNS server is
 complicated by the fact that it involves configuration of external DNS
 servers to provide delegation. We will walk through three scenarios of
@@ -1733,8 +2447,8 @@ for which dnsmasq is authoritative our.zone.com.
 The simplest configuration consists of two lines of dnsmasq configuration; something like
 
 .nf
-.B auth-server=server.example.com,eth0
-.B auth-zone=our.zone.com,1.2.3.0/24
+.B --auth-server=server.example.com,eth0
+.B --auth-zone=our.zone.com,1.2.3.0/24
 .fi
 
 and two records in the external DNS
@@ -1757,8 +2471,8 @@ authoritative zone which dnsmasq is serving, typically
 we have
 
 .nf
-.B auth-server=our.zone.com,eth0
-.B auth-zone=our.zone.com,1.2.3.0/24
+.B --auth-server=our.zone.com,eth0
+.B --auth-zone=our.zone.com,1.2.3.0/24
 .fi
 
 .nf
@@ -1777,23 +2491,27 @@ entry or 
 .B --host-record.
 
 .nf
-.B auth-server=our.zone.com,eth0
-.B host-record=our.zone.com,1.2.3.4
-.B auth-zone=our.zone.com,1.2.3.0/24
+.B --auth-server=our.zone.com,eth0
+.B --host-record=our.zone.com,1.2.3.4
+.B --auth-zone=our.zone.com,1.2.3.0/24
 .fi
 
 If the external address is dynamic, the address
 associated with our.zone.com must be derived from the address of the
 relevant interface. This is done using 
-.B interface-name
+.B --interface-name
 Something like:
 
 .nf
-.B auth-server=our.zone.com,eth0
-.B interface-name=our.zone.com,eth0
-.B auth-zone=our.zone.com,1.2.3.0/24
+.B --auth-server=our.zone.com,eth0
+.B --interface-name=our.zone.com,eth0
+.B --auth-zone=our.zone.com,1.2.3.0/24,eth0
 .fi
 
+(The "eth0" argument in \fB--auth-zone\fP adds the subnet containing eth0's
+dynamic address to the zone, so that the \fB--interface-name\fP returns the
+address in outside queries.)
+
 Our final configuration builds on that above, but also adds a
 secondary DNS server. This is another DNS server which learns the DNS data
 for the zone by doing zones transfer, and acts as a backup should
@@ -1802,7 +2520,7 @@ secondary is beyond the scope of this man-page, but th
 configuration of dnsmasq is simple:
 
 .nf
-.B auth-sec-servers=secondary.myisp.com
+.B --auth-sec-servers=secondary.myisp.com
 .fi
 
 and
@@ -1816,13 +2534,13 @@ secondary to collect the DNS data. If you wish to rest
 to particular hosts then
 
 .nf
-.B auth-peer=<IP address of secondary>
+.B --auth-peer=<IP address of secondary>
 .fi
 
 will do so.
 
 Dnsmasq acts as an authoritative server for  in-addr.arpa and
-ipv6.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
 configured with a suitable NS record, for instance in this example,
 where we allow 1.2.3.0/24 addresses.
@@ -1839,30 +2557,43 @@ secondary servers for reverse lookups.
 When dnsmasq is configured to act as an authoritative server, the
 following data is used to populate the authoritative zone.
 .PP
-.B --mx-host, --srv-host, --dns-rr, --txt-record, --naptr-record
-, as long as the record names are in the authoritative domain.
+.B --mx-host, --srv-host, --dns-rr, --txt-record, --naptr-record, --caa-record,
+as long as the record names are in the authoritative domain.
 .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
 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
-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
 IPv4 and IPv6 addresses from /etc/hosts (and 
 .B --addn-hosts
 ) and
 .B --host-record
+and 
+.B --interface-name
+and
+.B ---dynamic-host
 provided the address falls into one of the subnets specified in the
 .B --auth-zone.
 .PP
-Addresses specified by 
-.B --interface-name.
-In this case, the address is not contrained to a subnet from
-.B --auth-zone. 
-
-.PP
 Addresses of DHCP leases, provided the address falls into one of the subnets specified in the
+.B --auth-zone.
+(If constructed DHCP ranges are is use, which depend on the address dynamically 
+assigned to an interface, then the form of
 .B --auth-zone
-OR a constructed DHCP range. In the default mode, where a DHCP lease
+which defines subnets by the dynamic address of an interface should
+be used to ensure this condition is met.)
+.PP 
+In the default mode, where a DHCP lease
 has an unqualified name, and possibly a qualified name constructed
 using 
 .B --domain
@@ -1878,7 +2609,6 @@ used, and must match the zone's domain.
 
 
 .SH EXIT CODES
-.PP
 0 - Dnsmasq successfully forked into the background, or terminated
 normally if backgrounding is not enabled.
 .PP
@@ -1895,7 +2625,9 @@ file/directory, permissions).
 5 - Other miscellaneous problem.
 .PP
 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. 
 
 .SH LIMITS