version 1.1, 2012/02/21 22:30:18
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version 1.1.1.1, 2012/10/09 09:06:54
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.\" $Id$ |
.\" $Id$ |
.\" |
.\" |
.\" Copyright (c) 2009-2011 by Internet Systems Consortium, Inc. ("ISC") | .\" Copyright (c) 2009-2012 by Internet Systems Consortium, Inc. ("ISC") |
.\" Copyright (c) 2004,2007 by Internet Systems Consortium, Inc. ("ISC") |
.\" Copyright (c) 2004,2007 by Internet Systems Consortium, Inc. ("ISC") |
.\" Copyright (c) 1996-2003 by Internet Software Consortium |
.\" Copyright (c) 1996-2003 by Internet Software Consortium |
.\" |
.\" |
Line 36 The dhclient.conf file contains configuration informat
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Line 36 The dhclient.conf file contains configuration informat
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.IR dhclient, |
.IR dhclient, |
the Internet Systems Consortium DHCP Client. |
the Internet Systems Consortium DHCP Client. |
.PP |
.PP |
The dhclient.conf file is a free-form ASCII text file. It is parsed by | The dhclient.conf file is a free-form ASCII text file. It is parsed by |
the recursive-descent parser built into dhclient. The file may contain | the recursive-descent parser built into dhclient. The file may contain |
extra tabs and newlines for formatting purposes. Keywords in the file |
extra tabs and newlines for formatting purposes. Keywords in the file |
are case-insensitive. Comments may be placed anywhere within the | are case-insensitive. Comments may be placed anywhere within the |
file (except within quotes). Comments begin with the # character and | file (except within quotes). Comments begin with the # character and |
end at the end of the line. |
end at the end of the line. |
.PP |
.PP |
The dhclient.conf file can be used to configure the behaviour of the |
The dhclient.conf file can be used to configure the behaviour of the |
Line 74 The
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Line 74 The
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statement determines the amount of time that must pass between the |
statement determines the amount of time that must pass between the |
time that the client begins to try to determine its address and the |
time that the client begins to try to determine its address and the |
time that it decides that it's not going to be able to contact a |
time that it decides that it's not going to be able to contact a |
server. By default, this timeout is sixty seconds. After the | server. By default, this timeout is sixty seconds. After the |
timeout has passed, if there are any static leases defined in the |
timeout has passed, if there are any static leases defined in the |
configuration file, or any leases remaining in the lease database that |
configuration file, or any leases remaining in the lease database that |
have not yet expired, the client will loop through these leases |
have not yet expired, the client will loop through these leases |
attempting to validate them, and if it finds one that appears to be |
attempting to validate them, and if it finds one that appears to be |
valid, it will use that lease's address. If there are no valid | valid, it will use that lease's address. If there are no valid |
static leases or unexpired leases in the lease database, the client |
static leases or unexpired leases in the lease database, the client |
will restart the protocol after the defined retry interval. |
will restart the protocol after the defined retry interval. |
.PP |
.PP |
Line 93 The
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Line 93 The
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.I retry |
.I retry |
statement determines the time that must pass after the client has |
statement determines the time that must pass after the client has |
determined that there is no DHCP server present before it tries again |
determined that there is no DHCP server present before it tries again |
to contact a DHCP server. By default, this is five minutes. | to contact a DHCP server. By default, this is five minutes. |
.PP |
.PP |
.I The |
.I The |
.B select-timeout |
.B select-timeout |
Line 102 to contact a DHCP server. By default, this is five m
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Line 102 to contact a DHCP server. By default, this is five m
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\fBselect-timeout \fItime\fR\fB;\fR |
\fBselect-timeout \fItime\fR\fB;\fR |
.PP |
.PP |
It is possible (some might say desirable) for there to be more than |
It is possible (some might say desirable) for there to be more than |
one DHCP server serving any given network. In this case, it is | one DHCP server serving any given network. In this case, it is |
possible that a client may be sent more than one offer in response to |
possible that a client may be sent more than one offer in response to |
its initial lease discovery message. It may be that one of these | its initial lease discovery message. It may be that one of these |
offers is preferable to the other (e.g., one offer may have the |
offers is preferable to the other (e.g., one offer may have the |
address the client previously used, and the other may not). |
address the client previously used, and the other may not). |
.PP |
.PP |
Line 112 The
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Line 112 The
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.I select-timeout |
.I select-timeout |
is the time after the client sends its first lease discovery request |
is the time after the client sends its first lease discovery request |
at which it stops waiting for offers from servers, assuming that it |
at which it stops waiting for offers from servers, assuming that it |
has received at least one such offer. If no offers have been | has received at least one such offer. If no offers have been |
received by the time the |
received by the time the |
.I select-timeout |
.I select-timeout |
has expired, the client will accept the first offer that arrives. |
has expired, the client will accept the first offer that arrives. |
Line 127 will take the first offer it sees.
|
Line 127 will take the first offer it sees.
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\fBreboot \fItime\fR\fB;\fR |
\fBreboot \fItime\fR\fB;\fR |
.PP |
.PP |
When the client is restarted, it first tries to reacquire the last |
When the client is restarted, it first tries to reacquire the last |
address it had. This is called the INIT-REBOOT state. If it is | address it had. This is called the INIT-REBOOT state. If it is |
still attached to the same network it was attached to when it last |
still attached to the same network it was attached to when it last |
ran, this is the quickest way to get started. The | ran, this is the quickest way to get started. The |
.I reboot |
.I reboot |
statement sets the time that must elapse after the client first tries |
statement sets the time that must elapse after the client first tries |
to reacquire its old address before it gives up and tries to discover |
to reacquire its old address before it gives up and tries to discover |
a new address. By default, the reboot timeout is ten seconds. | a new address. By default, the reboot timeout is ten seconds. |
.PP |
.PP |
.I The |
.I The |
.B backoff-cutoff |
.B backoff-cutoff |
Line 143 a new address. By default, the reboot timeout is ten
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Line 143 a new address. By default, the reboot timeout is ten
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.PP |
.PP |
The client uses an exponential backoff algorithm with some randomness, |
The client uses an exponential backoff algorithm with some randomness, |
so that if many clients try to configure themselves at the same time, |
so that if many clients try to configure themselves at the same time, |
they will not make their requests in lockstep. The | they will not make their requests in lockstep. The |
.I backoff-cutoff |
.I backoff-cutoff |
statement determines the maximum amount of time that the client is |
statement determines the maximum amount of time that the client is |
allowed to back off, the actual value will be evaluated randomly between |
allowed to back off, the actual value will be evaluated randomly between |
1/2 to 1 1/2 times the \fItime\fR specified. It defaults to two minutes. | 1/2 to 1 1/2 times the \fItime\fR specified. It defaults to fifteen |
| seconds. |
.PP |
.PP |
.I The |
.I The |
.B initial-interval |
.B initial-interval |
Line 181 to 5.
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Line 182 to 5.
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.SH LEASE REQUIREMENTS AND REQUESTS |
.SH LEASE REQUIREMENTS AND REQUESTS |
The DHCP protocol allows the client to request that the server send it |
The DHCP protocol allows the client to request that the server send it |
specific information, and not send it other information that it is not |
specific information, and not send it other information that it is not |
prepared to accept. The protocol also allows the client to reject | prepared to accept. The protocol also allows the client to reject |
offers from servers if they don't contain information the client |
offers from servers if they don't contain information the client |
needs, or if the information provided is not satisfactory. |
needs, or if the information provided is not satisfactory. |
.PP |
.PP |
Line 198 are called \fIDHCP Options\fR. DHCP Options are defin
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Line 199 are called \fIDHCP Options\fR. DHCP Options are defin
|
.PP |
.PP |
The request statement causes the client to request that any server |
The request statement causes the client to request that any server |
responding to the client send the client its values for the specified |
responding to the client send the client its values for the specified |
options. Only the option names should be specified in the request | options. Only the option names should be specified in the request |
statement - not option parameters. By default, the DHCPv4 client | statement - not option parameters. By default, the DHCPv4 client |
requests the subnet-mask, broadcast-address, time-offset, routers, |
requests the subnet-mask, broadcast-address, time-offset, routers, |
domain-name, domain-name-servers and host-name options while the DHCPv6 |
domain-name, domain-name-servers and host-name options while the DHCPv6 |
client requests the dhcp6 name-servers and domain-search options. Note |
client requests the dhcp6 name-servers and domain-search options. Note |
Line 207 that if you enter a \'request\' statement, you over-ri
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Line 208 that if you enter a \'request\' statement, you over-ri
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and these options will not be requested. |
and these options will not be requested. |
.PP |
.PP |
In some cases, it may be desirable to send no parameter request list |
In some cases, it may be desirable to send no parameter request list |
at all. To do this, simply write the request statement but specify | at all. To do this, simply write the request statement but specify |
no parameters: |
no parameters: |
.PP |
.PP |
.nf |
.nf |
Line 229 is best to \'also request\' the additional options:
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Line 230 is best to \'also request\' the additional options:
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\fB[ also ] require [ [ \fIoption-space\fR . ] \fIoption\fR ] [\fB,\fI ... ]\fB;\fR |
\fB[ also ] require [ [ \fIoption-space\fR . ] \fIoption\fR ] [\fB,\fI ... ]\fB;\fR |
.PP |
.PP |
The require statement lists options that must be sent in order for an |
The require statement lists options that must be sent in order for an |
offer to be accepted. Offers that do not contain all the listed | offer to be accepted. Offers that do not contain all the listed |
options will be ignored. There is no default require list. |
options will be ignored. There is no default require list. |
.PP |
.PP |
.nf |
.nf |
Line 257 that will allow it to differentiate between this clien
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Line 258 that will allow it to differentiate between this clien
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clients or kinds of clients. |
clients or kinds of clients. |
.SH DYNAMIC DNS |
.SH DYNAMIC DNS |
The client now has some very limited support for doing DNS updates |
The client now has some very limited support for doing DNS updates |
when a lease is acquired. This is prototypical, and probably doesn't | when a lease is acquired. This is prototypical, and probably doesn't |
do what you want. It also only works if you happen to have control | do what you want. It also only works if you happen to have control |
over your DNS server, which isn't very likely. |
over your DNS server, which isn't very likely. |
.PP |
.PP |
Note that everything in this section is true whether you are using DHCPv4 |
Note that everything in this section is true whether you are using DHCPv4 |
or DHCPv6. The exact same syntax is used for both. |
or DHCPv6. The exact same syntax is used for both. |
.PP |
.PP |
To make it work, you have to declare a key and zone as in the DHCP |
To make it work, you have to declare a key and zone as in the DHCP |
server (see \fBdhcpd.conf\fR(5) for details). You also need to | server (see \fBdhcpd.conf\fR(5) for details). You also need to |
configure the fqdn option on the client, as follows: |
configure the fqdn option on the client, as follows: |
.PP |
.PP |
.nf |
.nf |
Line 276 configure the fqdn option on the client, as follows:
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Line 277 configure the fqdn option on the client, as follows:
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.fi |
.fi |
.PP |
.PP |
The \fIfqdn.fqdn\fR option \fBMUST\fR be a fully-qualified domain |
The \fIfqdn.fqdn\fR option \fBMUST\fR be a fully-qualified domain |
name. You \fBMUST\fR define a zone statement for the zone to be | name. You \fBMUST\fR define a zone statement for the zone to be |
updated. The \fIfqdn.encoded\fR option may need to be set to | updated. The \fIfqdn.encoded\fR option may need to be set to |
\fIon\fR or \fIoff\fR, depending on the DHCP server you are using. |
\fIon\fR or \fIoff\fR, depending on the DHCP server you are using. |
.PP |
.PP |
.I The |
.I The |
Line 291 script (see \fBdhclient-script(8)\fR) rather than havi
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Line 292 script (see \fBdhclient-script(8)\fR) rather than havi
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DHCP client do the update directly (for example, if you want to |
DHCP client do the update directly (for example, if you want to |
use SIG(0) authentication, which is not supported directly by the |
use SIG(0) authentication, which is not supported directly by the |
DHCP client, you can instruct the client not to do the update using |
DHCP client, you can instruct the client not to do the update using |
the \fBdo-forward-updates\fR statement. \fIFlag\fR should be \fBtrue\fR | the \fBdo-forward-updates\fR statement. \fIFlag\fR should be \fBtrue\fR |
if you want the DHCP client to do the update, and \fBfalse\fR if |
if you want the DHCP client to do the update, and \fBfalse\fR if |
you don't want the DHCP client to do the update. By default, the DHCP | you don't want the DHCP client to do the update. By default, the DHCP |
client will do the DNS update. |
client will do the DNS update. |
.SH OPTION MODIFIERS |
.SH OPTION MODIFIERS |
In some cases, a client may receive option data from the server which |
In some cases, a client may receive option data from the server which |
is not really appropriate for that client, or may not receive |
is not really appropriate for that client, or may not receive |
information that it needs, and for which a useful default value |
information that it needs, and for which a useful default value |
exists. It may also receive information which is useful, but which | exists. It may also receive information which is useful, but which |
needs to be supplemented with local information. To handle these | needs to be supplemented with local information. To handle these |
needs, several option modifiers are available. |
needs, several option modifiers are available. |
.PP |
.PP |
.I The |
.I The |
Line 337 If for some set of options the client should use a val
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Line 338 If for some set of options the client should use a val
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supply, and then use the values supplied by |
supply, and then use the values supplied by |
the server, if any, these values can be defined in the |
the server, if any, these values can be defined in the |
.B prepend |
.B prepend |
statement. The | statement. The |
.B prepend |
.B prepend |
statement can only be used for options which |
statement can only be used for options which |
allow more than one value to be given. This restriction is not | allow more than one value to be given. This restriction is not |
enforced - if you ignore it, the behaviour will be unpredictable. |
enforced - if you ignore it, the behaviour will be unpredictable. |
.PP |
.PP |
.I The |
.I The |
Line 353 If for some set of options the client should first use
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Line 354 If for some set of options the client should first use
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supplied by the server, if any, and then use values you supply, these |
supplied by the server, if any, and then use values you supply, these |
values can be defined in the |
values can be defined in the |
.B append |
.B append |
statement. The | statement. The |
.B append |
.B append |
statement can only be used for options which |
statement can only be used for options which |
allow more than one value to be given. This restriction is not | allow more than one value to be given. This restriction is not |
enforced - if you ignore it, the behaviour will be unpredictable. |
enforced - if you ignore it, the behaviour will be unpredictable. |
.SH LEASE DECLARATIONS |
.SH LEASE DECLARATIONS |
.PP |
.PP |
Line 368 enforced - if you ignore it, the behaviour will be unp
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Line 369 enforced - if you ignore it, the behaviour will be unp
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.PP |
.PP |
The DHCP client may decide after some period of time (see \fBPROTOCOL |
The DHCP client may decide after some period of time (see \fBPROTOCOL |
TIMING\fR) that it is not going to succeed in contacting a |
TIMING\fR) that it is not going to succeed in contacting a |
server. At that time, it consults its own database of old leases and | server. At that time, it consults its own database of old leases and |
tests each one that has not yet timed out by pinging the listed router |
tests each one that has not yet timed out by pinging the listed router |
for that lease to see if that lease could work. It is possible to | for that lease to see if that lease could work. It is possible to |
define one or more \fIfixed\fR leases in the client configuration file |
define one or more \fIfixed\fR leases in the client configuration file |
for networks where there is no DHCP or BOOTP service, so that the |
for networks where there is no DHCP or BOOTP service, so that the |
client can still automatically configure its address. This is done | client can still automatically configure its address. This is done |
with the |
with the |
.B lease |
.B lease |
statement. |
statement. |
Line 381 statement.
|
Line 382 statement.
|
NOTE: the lease statement is also used in the dhclient.leases file in |
NOTE: the lease statement is also used in the dhclient.leases file in |
order to record leases that have been received from DHCP servers. |
order to record leases that have been received from DHCP servers. |
Some of the syntax for leases as described below is only needed in the |
Some of the syntax for leases as described below is only needed in the |
dhclient.leases file. Such syntax is documented here for | dhclient.leases file. Such syntax is documented here for |
completeness. |
completeness. |
.PP |
.PP |
A lease statement consists of the lease keyword, followed by a left |
A lease statement consists of the lease keyword, followed by a left |
curly brace, followed by one or more lease declaration statements, |
curly brace, followed by one or more lease declaration statements, |
followed by a right curly brace. The following lease declarations | followed by a right curly brace. The following lease declarations |
are possible: |
are possible: |
.PP |
.PP |
\fBbootp;\fR |
\fBbootp;\fR |
Line 394 are possible:
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Line 395 are possible:
|
The |
The |
.B bootp |
.B bootp |
statement is used to indicate that the lease was acquired using the |
statement is used to indicate that the lease was acquired using the |
BOOTP protocol rather than the DHCP protocol. It is never necessary | BOOTP protocol rather than the DHCP protocol. It is never necessary |
to specify this in the client configuration file. The client uses | to specify this in the client configuration file. The client uses |
this syntax in its lease database file. |
this syntax in its lease database file. |
.PP |
.PP |
\fBinterface\fR \fB"\fR\fIstring\fR\fB";\fR |
\fBinterface\fR \fB"\fR\fIstring\fR\fB";\fR |
Line 403 this syntax in its lease database file.
|
Line 404 this syntax in its lease database file.
|
The |
The |
.B interface |
.B interface |
lease statement is used to indicate the interface on which the lease |
lease statement is used to indicate the interface on which the lease |
is valid. If set, this lease will only be tried on a particular | is valid. If set, this lease will only be tried on a particular |
interface. When the client receives a lease from a server, it always | interface. When the client receives a lease from a server, it always |
records the interface number on which it received that lease. |
records the interface number on which it received that lease. |
If predefined leases are specified in the dhclient.conf file, the |
If predefined leases are specified in the dhclient.conf file, the |
interface should also be specified, although this is not required. |
interface should also be specified, although this is not required. |
Line 413 interface should also be specified, although this is n
|
Line 414 interface should also be specified, although this is n
|
.PP |
.PP |
The |
The |
.B fixed-address |
.B fixed-address |
statement is used to set the ip address of a particular lease. This | statement is used to set the ip address of a particular lease. This |
is required for all lease statements. The IP address must be | is required for all lease statements. The IP address must be |
specified as a dotted quad (e.g., 12.34.56.78). |
specified as a dotted quad (e.g., 12.34.56.78). |
.PP |
.PP |
\fBfilename "\fR\fIstring\fR\fB";\fR |
\fBfilename "\fR\fIstring\fR\fB";\fR |
.PP |
.PP |
The |
The |
.B filename |
.B filename |
statement specifies the name of the boot filename to use. This is | statement specifies the name of the boot filename to use. This is |
not used by the standard client configuration script, but is included |
not used by the standard client configuration script, but is included |
for completeness. |
for completeness. |
.PP |
.PP |
Line 429 for completeness.
|
Line 430 for completeness.
|
.PP |
.PP |
The |
The |
.B server-name |
.B server-name |
statement specifies the name of the boot server name to use. This is | statement specifies the name of the boot server name to use. This is |
also not used by the standard client configuration script. |
also not used by the standard client configuration script. |
.PP |
.PP |
\fBoption\fR \fIoption-declaration\fR\fB;\fR |
\fBoption\fR \fIoption-declaration\fR\fB;\fR |
Line 449 statement is used to specify the pathname of the dhcp
|
Line 450 statement is used to specify the pathname of the dhcp
|
configuration script. This script is used by the dhcp client to set |
configuration script. This script is used by the dhcp client to set |
each interface's initial configuration prior to requesting an address, |
each interface's initial configuration prior to requesting an address, |
to test the address once it has been offered, and to set the |
to test the address once it has been offered, and to set the |
interface's final configuration once a lease has been acquired. If | interface's final configuration once a lease has been acquired. If |
no lease is acquired, the script is used to test predefined leases, if |
no lease is acquired, the script is used to test predefined leases, if |
any, and also called once if no valid lease can be identified. For | any, and also called once if no valid lease can be identified. For |
more information, see |
more information, see |
.B dhclient-script(8). |
.B dhclient-script(8). |
.PP |
.PP |
Line 462 The
|
Line 463 The
|
statement is used to specify which option space should be used for |
statement is used to specify which option space should be used for |
decoding the vendor-encapsulate-options option if one is received. |
decoding the vendor-encapsulate-options option if one is received. |
The \fIdhcp-vendor-identifier\fR can be used to request a specific |
The \fIdhcp-vendor-identifier\fR can be used to request a specific |
class of vendor options from the server. See | class of vendor options from the server. See |
.B dhcp-options(5) |
.B dhcp-options(5) |
for details. |
for details. |
.PP |
.PP |
Line 493 interface requires media type configuration.
|
Line 494 interface requires media type configuration.
|
.PP |
.PP |
The \fBrenew\fR statement defines the time at which the dhcp client |
The \fBrenew\fR statement defines the time at which the dhcp client |
should begin trying to contact its server to renew a lease that it is |
should begin trying to contact its server to renew a lease that it is |
using. The \fBrebind\fR statement defines the time at which the dhcp | using. The \fBrebind\fR statement defines the time at which the dhcp |
client should begin to try to contact \fIany\fR dhcp server in order |
client should begin to try to contact \fIany\fR dhcp server in order |
to renew its lease. The \fBexpire\fR statement defines the time at | to renew its lease. The \fBexpire\fR statement defines the time at |
which the dhcp client must stop using a lease if it has not been able |
which the dhcp client must stop using a lease if it has not been able |
to contact a server in order to renew it. |
to contact a server in order to renew it. |
.PP |
.PP |
Line 547 instead of an actual date.
|
Line 548 instead of an actual date.
|
Some DHCP clients running TCP/IP roaming protocols may require that in |
Some DHCP clients running TCP/IP roaming protocols may require that in |
addition to the lease they may acquire via DHCP, their interface also |
addition to the lease they may acquire via DHCP, their interface also |
be configured with a predefined IP alias so that they can have a |
be configured with a predefined IP alias so that they can have a |
permanent IP address even while roaming. The Internet Systems | permanent IP address even while roaming. The Internet Systems |
Consortium DHCP client doesn't support roaming with fixed addresses |
Consortium DHCP client doesn't support roaming with fixed addresses |
directly, but in order to facilitate such experimentation, the dhcp |
directly, but in order to facilitate such experimentation, the dhcp |
client can be set up to configure an IP alias using the |
client can be set up to configure an IP alias using the |
Line 559 options other than the subnet-mask option are ignored
|
Line 560 options other than the subnet-mask option are ignored
|
client configuration script, and expiry times are ignored. A typical |
client configuration script, and expiry times are ignored. A typical |
alias declaration includes an interface declaration, a fixed-address |
alias declaration includes an interface declaration, a fixed-address |
declaration for the IP alias address, and a subnet-mask option |
declaration for the IP alias address, and a subnet-mask option |
declaration. A medium statement should never be included in an alias | declaration. A medium statement should never be included in an alias |
declaration. |
declaration. |
.SH OTHER DECLARATIONS |
.SH OTHER DECLARATIONS |
\fBdb-time-format\fR [ \fIdefault\fR | \fIlocal\fR ] \fB;\fR |
\fBdb-time-format\fR [ \fIdefault\fR | \fIlocal\fR ] \fB;\fR |
Line 588 the subnet, counting the number of significant bits in
|
Line 589 the subnet, counting the number of significant bits in
|
from the leftmost end. Example configuration syntax: |
from the leftmost end. Example configuration syntax: |
.PP |
.PP |
.I \fIreject\fR 192.168.0.0\fB/\fR16\fB,\fR 10.0.0.5\fB;\fR |
.I \fIreject\fR 192.168.0.0\fB/\fR16\fB,\fR 10.0.0.5\fB;\fR |
.RE |
|
.PP |
.PP |
The above example would cause offers from any server identifier in the |
The above example would cause offers from any server identifier in the |
entire RFC 1918 "Class C" network 192.168.0.0/16, or the specific |
entire RFC 1918 "Class C" network 192.168.0.0/16, or the specific |
Line 597 single address 10.0.0.5, to be rejected.
|
Line 597 single address 10.0.0.5, to be rejected.
|
\fBinterface "\fIname\fB" { \fIdeclarations ... \fB } |
\fBinterface "\fIname\fB" { \fIdeclarations ... \fB } |
.PP |
.PP |
A client with more than one network interface may require different |
A client with more than one network interface may require different |
behaviour depending on which interface is being configured. All | behaviour depending on which interface is being configured. All |
timing parameters and declarations other than lease and alias |
timing parameters and declarations other than lease and alias |
declarations can be enclosed in an interface declaration, and those |
declarations can be enclosed in an interface declaration, and those |
parameters will then be used only for the interface that matches the |
parameters will then be used only for the interface that matches the |
specified name. Interfaces for which there is no interface | specified name. Interfaces for which there is no interface |
declaration will use the parameters declared outside of any interface |
declaration will use the parameters declared outside of any interface |
declaration, or the default settings. |
declaration, or the default settings. |
.PP |
.PP |
Line 622 Each interface that the DHCP client is supporting norm
|
Line 622 Each interface that the DHCP client is supporting norm
|
client state machine running on it to acquire and maintain its lease. |
client state machine running on it to acquire and maintain its lease. |
A pseudo-interface is just another state machine running on the |
A pseudo-interface is just another state machine running on the |
interface named \fIreal-name\fR, with its own lease and its own |
interface named \fIreal-name\fR, with its own lease and its own |
state. If you use this feature, you must provide a client identifier | state. If you use this feature, you must provide a client identifier |
for both the pseudo-interface and the actual interface, and the two |
for both the pseudo-interface and the actual interface, and the two |
identifiers must be different. You must also provide a separate | identifiers must be different. You must also provide a separate |
client script for the pseudo-interface to do what you want with the IP |
client script for the pseudo-interface to do what you want with the IP |
address. For example: | address. For example: |
.PP |
.PP |
.nf |
.nf |
interface "ep0" { |
interface "ep0" { |
Line 641 address. For example:
|
Line 641 address. For example:
|
The client script for the pseudo-interface should not configure the |
The client script for the pseudo-interface should not configure the |
interface up or down - essentially, all it needs to handle are the |
interface up or down - essentially, all it needs to handle are the |
states where a lease has been acquired or renewed, and the states |
states where a lease has been acquired or renewed, and the states |
where a lease has expired. See \fBdhclient-script(8)\fR for more | where a lease has expired. See \fBdhclient-script(8)\fR for more |
information. |
information. |
.PP |
.PP |
\fBmedia "\fImedia setup\fB"\fI [ \fB, "\fImedia setup\fB", \fI... ]\fB;\fR |
\fBmedia "\fImedia setup\fB"\fI [ \fB, "\fImedia setup\fB", \fI... ]\fB;\fR |
Line 649 information.
|
Line 649 information.
|
The |
The |
.B media |
.B media |
statement defines one or more media configuration parameters which may |
statement defines one or more media configuration parameters which may |
be tried while attempting to acquire an IP address. The dhcp client | be tried while attempting to acquire an IP address. The dhcp client |
will cycle through each media setup string on the list, configuring |
will cycle through each media setup string on the list, configuring |
the interface using that setup and attempting to boot, and then trying |
the interface using that setup and attempting to boot, and then trying |
the next one. This can be used for network interfaces which aren't | the next one. This can be used for network interfaces which aren't |
capable of sensing the media type unaided - whichever media type |
capable of sensing the media type unaided - whichever media type |
succeeds in getting a request to the server and hearing the reply is |
succeeds in getting a request to the server and hearing the reply is |
probably right (no guarantees). |
probably right (no guarantees). |
.PP |
.PP |
The media setup is only used for the initial phase of address |
The media setup is only used for the initial phase of address |
acquisition (the DHCPDISCOVER and DHCPOFFER packets). Once an | acquisition (the DHCPDISCOVER and DHCPOFFER packets). Once an |
address has been acquired, the dhcp client will record it in its lease |
address has been acquired, the dhcp client will record it in its lease |
database and will record the media type used to acquire the address. |
database and will record the media type used to acquire the address. |
Whenever the client tries to renew the lease, it will use that same |
Whenever the client tries to renew the lease, it will use that same |
media type. The lease must expire before the client will go back to | media type. The lease must expire before the client will go back to |
cycling through media types. |
cycling through media types. |
.SH SAMPLE |
.SH SAMPLE |
The following configuration file is used on a laptop running NetBSD |
The following configuration file is used on a laptop running NetBSD |
1.3. The laptop has an IP alias of 192.5.5.213, and has one | 1.3. The laptop has an IP alias of 192.5.5.213, and has one |
interface, ep0 (a 3com 3C589C). Booting intervals have been | interface, ep0 (a 3com 3C589C). Booting intervals have been |
shortened somewhat from the default, because the client is known to |
shortened somewhat from the default, because the client is known to |
spend most of its time on networks with little DHCP activity. The | spend most of its time on networks with little DHCP activity. The |
laptop does roam to multiple networks. |
laptop does roam to multiple networks. |
|
|
.nf |
.nf |
Line 701 alias {
|
Line 701 alias {
|
} |
} |
.fi |
.fi |
This is a very complicated dhclient.conf file - in general, yours |
This is a very complicated dhclient.conf file - in general, yours |
should be much simpler. In many cases, it's sufficient to just | should be much simpler. In many cases, it's sufficient to just |
create an empty dhclient.conf file - the defaults are usually fine. |
create an empty dhclient.conf file - the defaults are usually fine. |
.SH SEE ALSO |
.SH SEE ALSO |
dhcp-options(5), dhcp-eval(5), dhclient.leases(5), dhcpd(8), dhcpd.conf(5), |
dhcp-options(5), dhcp-eval(5), dhclient.leases(5), dhcpd(8), dhcpd.conf(5), |
Line 709 RFC2132, RFC2131.
|
Line 709 RFC2132, RFC2131.
|
.SH AUTHOR |
.SH AUTHOR |
.B dhclient(8) |
.B dhclient(8) |
was written by Ted Lemon |
was written by Ted Lemon |
under a contract with Vixie Labs. Funding | under a contract with Vixie Labs. Funding |
for this project was provided by Internet Systems Consortium. |
for this project was provided by Internet Systems Consortium. |
Information about Internet Systems Consortium can be found at |
Information about Internet Systems Consortium can be found at |
.B https://www.isc.org. |
.B https://www.isc.org. |