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Files Reference
Default configuration information
for the Dynamic Host Configuration Protocol (DHCP) client program
(dhcpcd).
The dhcpcd configuration file
contains entries for logging information, requested options, interfaces to
configure, and other items.
Following are the formats for the
data in the configuration file.
- # Comment line
- The # character means that there is a comment from that point to the end
of the line.
- numLogFiles n
- Specifies the number of log files. If 0 is specified, no log file
will be maintained and no log message is displayed anywhere.
n is the maximum number of log files maintained as the size of the
most recent log file reaches its maximum size and a new log file is
created.
- logFileSize n
- Maximum size of a log file. When the size of the most recent log
file reaches this value, it is renamed and a new log file is created.
n is measured in kilobytes(KB).
- logFileName filename
- Name and path of the most recent log file. Less recent log files
have the number 1 to (n - 1) appended to their names; the larger the
number, the older the file.
- logItem <option
name>
- One item that will be logged. Multiple of these lines are
allowed. This allows for the specified logging level to be turned
on. The following are option names:
- SYSERR
- System error, at the interface to the platform
- OBJERR
- Object error, in between objects in the process
- PROTERR
- Protocol error, between client and server
- WARNING
- Warning, worth attention from the user
- EVENT
- Event occurred to the process
- ACTION
- Action taken by the process
- INFO
- Information that might be useful
- ACNTING
- Who was served, and when
- TRACE
- Code flow, for debugging.
-
-
- interface
<ifName>
- The interface to configure DHCP on. This may be the interface that
is to be configured. Multiples of these are allowed. There is a
special entry, any. This tells the DHCP client to configure
the first one it finds and completes successfully. If the
any option is used, there should not be any other interface
specified. The interface statement may be immediately followed by a
pair of curly braces, in which the options requested for this interface can be
specified. Options requested within interface curly braces apply only
to this interface. See DHCP Server
Configuration File for a list of options and formats.
- clientid <MAC |
HOSTNAME>
- Specifies the client id to use in all communication with the
server. MAC denotes that the hardware address for the particular
interface should be used as the client id. HOSTNAME denotes
that the domain host name should be used as the client id. The default
is MAC.
- sniffer <exec
string>
- Specifies a string enclosed in quotes, indicating a program to execute to
detect hardware failure/recovery for an interface. The dhcp client will
look for signal 23(SIGIO) to indicate that the network interface is up and
signal 16(SIGURG) to indicate that the network interface is down.
- option <code>
[<value>] [exec <string>]
- Specifies an option requested by this client. Its scope is
determined by whether it is inside a set of curly braces for a particular
interface, or if it is outside all curly braces. If outside, it applies
to all interfaces. code is the option code of the option
requested. value is the requested value for that
option. This value is passed to the server with the option. The
value is not required. The keyword exec denotes a string
following which should be executed if this option is returned by the
server. This string is expected to be an executable shell script or
program. An "%s" may be included in the string. If present, the
value returned by the server will be provided in ascii.
- vendor
- Specifies the special syntax for the specification of the vendor
extensions field. It is followed by a set of curly braces.
Inside the curly braces, the options and values for the vendor extensions
field are specified. The exec string on an option inside the vendor
extensions options is not valid. It is ignored.
- reject <code>
- Specifies that if this option code is returned by the server, this option
should be ignored by the client. Its value should not be used.
- otherOptions <accept |
reject>
- Specifies how all other options should be handled by the client.
This refers to any options not specifically requested with an "option"
statement or rejected with a "reject" statement. The default is that
all options are accepted.
- updateDNS
<string>
- A string enclosed in quotes, indicating a program to execute to update the
DNS server with the new inverse mapping for the IP address and names served by
dhcp. This string should include four %s's to indicate
the placement of the following information from the dhcp
client:
- hostname
- Value of option 12. The value returned by the dhcp
server is used, if one is supplied. Else, if the client specified a
value in this file, the client-requested value is used. If
neither the client specified a requested hostname nor the server supplied one,
this exec string will not be executed.
- domainname
- Value of option 15. The value returned by the dhcp
server is used, if one is supplied. Else, if the client specified a
value in this file, the client-requested value is used. If
neither the client specified a requested hostname nor the server supplied one,
a null string (" ") will be supplied by dhcp. Therefore,
this value is optional.
- Ip Address
- IP address leased to this client by the server. The string is
supplied in dotted notation, for example,
9.2.23.43.
- leasetime
- Lease time granted by the server. This string is a decimal number
representing the number of seconds of the lease.
These values are output by dhcp in this order:
hostname domainname Ip Address leasetime
A script
/usr/sbin/dhcpaction has been provided with this function, as well
as actions to help NIM interact with DHCP clients. Run the script as
follows:
/usr/sbin/dhcpaction hostname domainname ipaddress
leasetime < A | PTR | BOTH | NONE > NONIM
The first four parameters are
what will be used to update the DNS server. The fifth parameter tells
dhcpaction to update the A record, the PTR record, or both, or
none. The options are A, PTR, BOTH,
NONE. The sixth parameter is used to tell servers that NIM
is being used, and processing needs to be done when a client changes
address. The options for this are NIM and NONIM. On clients,
this must be set to NONIM.
An example follows:
updateDNS "/usr/sbin/dhcpaction %s %s %s %s PTR
NONIM 2>&1 >>/tmp/updns.out"
-
-
This example tells the
dhcpcd daemon to use log files of a maximum of 100Kb in size and at
most four of them.
The base name for the log files
is /usr/tmp/dhcpsd.log. The user also would like to
only log four of the nine possible log entry types. The user also
specified a string to use for updating the Dynamic Domain Name Server.
The user also specified that the clientid to the server should be
based on the mac-address of the interface adapter that is trying to be
configured. The user also specified that all options should be accepted
and instantiated (otheroptions accept), except for option 9
(reject 9).
The options the user specified
were the domain (option 15), but since this option is global to the interface
keywords, it applies to both interfaces.
Inside each interface, the
hostname is specified with option 12.
numLogFiles 4
logFileSize 100
logFileName /usr/tmp/dhcpsd.log
logItem SYSERR
logItem OBJERR
logItem PROTERR
logItem TRACE
updateDNS "nsupdate -h%s -d%s -i% %s"
clientid MAC
otheroptions accept
reject 9
option 15 "austin.ibm.com"
interface en0
{
option 12 "e-chisos"
}
interface tr0
{
option 12 "t-chisos"
}
This file is part of TCP/IP in
Network Support Facilities in Base Operating System (BOS) Runtime.
The dhcpcd Daemon
The DHCP Server Configuration File
TCP/IP Address
and Parameter Assignment - Dynamic Host Configuration Protocol (DHCP) in
AIX 5L Version 5.1 System Management Guide: Communications
and Networks.
Problems with
Dynamic Host Configuration Protocol (DHCP) in AIX 5L Version
5.1 System Management Guide: Communications and
Networks.
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