1dhclient.conf(5) File Formats Manual dhclient.conf(5)
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6 dhclient.conf - DHCP client configuration file
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9 The dhclient.conf file contains configuration information for dhclient,
10 the Internet Systems Consortium DHCP Client.
11 The dhclient.conf file is a free-form ASCII text file. It is parsed by
13 the recursive-descent parser built into dhclient. The file may contain
14 extra tabs and newlines for formatting purposes. Keywords in the file
15 are case-insensitive. Comments may be placed anywhere within the file
16 (except within quotes). Comments begin with the # character and end at
17 the end of the line.
18 The dhclient.conf file can be used to configure the behaviour of the
20 client in a wide variety of ways: protocol timing, information
21 requested from the server, information required of the server, defaults
22 to use if the server does not provide certain information, values with
23 which to override information provided by the server, or values to
24 prepend or append to information provided by the server. The configu‐
25 ration file can also be preinitialized with addresses to use on net‐
26 works that don't have DHCP servers.
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29 The timing behaviour of the client need not be configured by the user.
30 If no timing configuration is provided by the user, a fairly reasonable
31 timing behaviour will be used by default - one which results in fairly
32 timely updates without placing an inordinate load on the server.
33 If required the following statements can be used to adjust the timing
35 behaviour of the DHCPv4 client. The DHCPv6 protocol provides values to
36 use and they are not currently configurable.
37 The timeout statement
39 timeout time;
41 The timeout statement determines the amount of time that must pass
43 between the time that the client begins to try to determine its address
44 and the time that it decides that it's not going to be able to contact
45 a server. By default, this timeout is sixty seconds. After the time‐
46 out has passed, if there are any static leases defined in the configu‐
47 ration file, or any leases remaining in the lease database that have
48 not yet expired, the client will loop through these leases attempting
49 to validate them, and if it finds one that appears to be valid, it will
50 use that lease's address. If there are no valid static leases or unex‐
51 pired leases in the lease database, the client will restart the proto‐
52 col after the defined retry interval.
53 The retry statement
55 retry time;
57 The retry statement determines the time that must pass after the client
59 has determined that there is no DHCP server present before it tries
60 again to contact a DHCP server. By default, this is five minutes.
61 The select-timeout statement
63 select-timeout time;
65 It is possible (some might say desirable) for there to be more than one
67 DHCP server serving any given network. In this case, it is possible