UDHCPC(8) GNU/Linux Administrator's Manual UDHCPC(8)NAMEudhcpc - very small DHCP client
SYNOPSISudhcpc [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 possi‐
ble 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 inter‐
face 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 mes‐
sage is optional, as the script will also be called with decon‐
fig if need be.
Parameters are passed to the script via the following environment vari‐
ables:
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
/usr/share/udhcpc/default.script
Script run when leases are obtained or lost.
NOTESudhcpc 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.
GNU/Linux 2001-09-26 UDHCPC(8)
