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.
