sourCEntral - mobile manpages

pdf

UDHCPC

NAME

udhcpc − very small DHCP client

SYNOPSIS

udhcpc [OPTION]...

DESCRIPTION

The udhcp client negotiates a lease with the DHCP server and executes a script when it is obtained or lost.

OPTIONS

−c CLIENTID, −−clientid=CLIENTID

Send the client identifier CLIENTID.

-f−−foreground

Do not fork after obtaining a lease.

−H HOSTNAME, −−hostname=HOSTNAME

Send the client hostname HOSTNAME.

−h HOSTNAME

Alias for -H HOSTNAME.

−i INTERFACE, −−interface=INTERFACE

Configure INTERFACE.

-n−−now

Exit with failure if a lease cannot be obtained.

−p FILE, −−pidfile=FILE

Write the process ID of the daemon to FILE.

-q−−quit

Exit after obtaining a lease.

−r ADDRESS, −−request=ADDRESS

Request IP address ADDRESS.

−s FILE, −−script=FILE

Use script FILE.

-v−−version

Display version.

USAGE

When an event occurs, udhcpc executes a script. There are four possible arguments to this script:
deconfig

deconfig is used when udhcpc starts, and when a lease is lost. The script should put the interface in an up, but deconfigured, state.

bound

bound is used when udhcpc moves from an unbound to a bound state. The script should configure the interface and set any other relevant parameters (e.g., default gateway, dns server, etc.).

renew

renew is used when udhcpc when a lease is renewed. The interface is already configured, so the IP address will not change. Other parameters (e.g., default gateway, subnet mask, dns server) may.

nak

nak is used when udhcpc receieves a NAK packet from the server. The enviromental variable $message will contain the reason for the NAK message if the server included one. Processing this message is optional, as the script will also be called with deconfig if need be.

Parameters are passed to the script via the following environment variables:

HOME

The inherited HOME, or "/" if it is unset.

PATH

The inherited PATH, or "/bin:/usr/bin:/sbin:/usr/sbin" if it is unset.

interface

The interface.

ip

The client IP address.

siaddr

The BOOTP next server option.

sname

The BOOTP server name option.

boot_file

The BOOTP boot file option.

subnet

The subnet mask.

timezone

The timezone offset from UTC in seconds.

router

The list of routers.

timesvr

The list of time servers.

namesvr

The list of IEN 116 name servers.

dns

The list of DNS servers.

logsvr

The list of MIT-LCS UDP log servers.

cookiesvr

The list of RFC 865 cookie servers.

lprsvr

The list of LPR servers.

hostname

The host name.

bootsize

The length in 512-octet blocks of the bootfile.

domain

The domain name of the network.

swapsvr

The client’s swap server.

rootpath

The path of the client’s root dist.

ipttl

The TTL.

mtu

The MTU.

broadcast

The broadcast address.

ntpsrv

The list of NTP servers.

wins

The list of WINS servers.

lease

The lease time in seconds.

dhcptype

The DHCP message type (safely ignored).

serverid

The server IP address.

message

Reason for a DHCPNAK.

tftp

The TFTP server name.

bootfile

The bootfile name.

FILES

/etc/udhcpc/default.script

Script run when leases are obtained or lost.

NOTES

udhcpc responds to the following signals:
SIGUSR1

This signal causes udhcpc to renew the current lease or, if it does not have one, obtain a new lease.

SIGUSR2

This signal caused udhcpc to release the current lease.

pdf