UDHCPD.CONF(5) GNU/Linux Administrator's Manual UDHCPD.CONF(5)NAME
udhcpd.conf - udhcp server configuration file
DESCRIPTION
The file /etc/udhcpd.conf contains configuration information specific to the udhcp server. It should contain one configuration keyword per
line, followed by appropriate configuration information.
OPTIONS
start ADDRESS
The starting address of the IP lease block is ADDRESS. The default is 192.168.0.20.
end ADDRESS
The ending address of the IP lease block is ADDRESS. The default is 192.168.0.254.
interface INTERFACE
The udhcp server should listen on INTERFACE. The default is eth0.
max_leases LEASES
Offer at most LEASES leases (including those reserved by OFFERs, DECLINEs, and ARP conflicts). The default is 254.
remaining REMAINING
If REMAINING is yes, store the time remaining for each lease. If it is no, store the expiration time for each lease. The default
is yes.
auto_time SECONDS
Write the lease information to a file every SECONDS seconds. The default is 7200.
decline_time SECONDS
Reserve an IP for SECONDS seconds if a DHCP decline message is received. The default is 3600.
conflict_time SECONDS
Reserve an IP for SECONDS seconds if an ARP conflict occurs. The default is 3600.
offer_time SECONDS
Reserve an IP for SECONDS seconds if it is offered. The default is 60.
min_lease SECONDS
Reserve an IP for the full lease time if the lease to be given is less than SECONDS seconds. The default is 60.
lease_file FILE
Write the lease information to FILE. The default is /var/lib/misc/udhcpd.leases.
pidfile FILE
Write the process ID to FILE. The default is /var/run/udhcpd.pid.
notify_file FILE
Execute FILE after the lease information is written. By default, no file is executed.
siaddr ADDRESS
BOOTP specific option. The default is 0.0.0.0.
sname NAME
BOOTP specific option. There is no default.
boot_file FILE
BOOTP specific option. There is no default.
option OPTION
DHCP specific option.
subnet ADDRESS
timezone OFFSET
router ADDRESS...
timesvr ADDRESS...
namesvr ADDRESS...
dns ADDRESS...
logsvr ADDRESS...
cookiesvr ADDRESS...
lprsvr ADDRESS...
hostname HOSTNAME
bootsize SIZE
domain DOMAIN
swapsvr ADDRESS
rootpath PATH
ipttl TTL
mtu MTU
broadcast ADDRESS
ntpsrv ADDRESS...
wins ADDRESS...
requestip ADDRESS
lease SECONDS
dhcptype TYPE
serverid ADDRESS
tftp FILE
bootfile FILE
The default for lease is 864000. There are no defaults for the other options.
SEE ALSO udhcpd(8).
GNU /Linux 2001-09-26 UDHCPD.CONF(5)
Check Out this Related Man Page
DHCLIENT(8) BSD System Manager's Manual DHCLIENT(8)NAME
dhclient -- Dynamic Host Configuration Protocol (DHCP) client
SYNOPSIS
dhclient [-bdqu] [-c file] [-l file] [-p file] interface
DESCRIPTION
The dhclient utility provides a means for configuring network interfaces using DHCP, BOOTP, or if these protocols fail, by statically assign-
ing an address.
The name of the network interface that dhclient should attempt to configure must be specified on the command line.
The options are as follows:
-b Forces dhclient to immediately move to the background.
-c file Specify an alternate location, file, for the configuration file.
-d Forces dhclient to always run as a foreground process. By default, dhclient runs in the foreground until it has configured the
interface, and then will revert to running in the background.
-l file Specify an alternate location, file, for the leases file.
-p file Specify an alternate location for the PID file. The default is /var/run/dhclient.interface.pid.
-q Forces dhclient to be less verbose on startup.
-u Forces dhclient to reject leases with unknown options in them. The default behaviour is to accept such lease offers.
The DHCP protocol allows a host to contact a central server which maintains a list of IP addresses which may be assigned on one or more sub-
nets. A DHCP client may request an address from this pool, and then use it on a temporary basis for communication on the network. The DHCP
protocol also provides a mechanism whereby a client can learn important details about the network to which it is attached, such as the loca-
tion of a default router, the location of a name server, and so on.
On startup, dhclient reads /etc/dhclient.conf for configuration instructions. It then gets a list of all the network interfaces that are
configured in the current system. It then attempts to configure each interface with DHCP.
In order to keep track of leases across system reboots and server restarts, dhclient keeps a list of leases it has been assigned in the
/var/db/dhclient.leases.IFNAME file. IFNAME represents the network interface of the DHCP client (e.g., em0), one for each interface. On
startup, after reading the dhclient.conf(5) file, dhclient reads the leases file to refresh its memory about what leases it has been
assigned.
Old leases are kept around in case the DHCP server is unavailable when dhclient is first invoked (generally during the initial system boot
process). In that event, old leases from the dhclient.leases.IFNAME file which have not yet expired are tested, and if they are determined
to be valid, they are used until either they expire or the DHCP server becomes available.
A mobile host which may sometimes need to access a network on which no DHCP server exists may be preloaded with a lease for a fixed address
on that network. When all attempts to contact a DHCP server have failed, dhclient will try to validate the static lease, and if it succeeds,
it will use that lease until it is restarted.
A mobile host may also travel to some networks on which DHCP is not available but BOOTP is. In that case, it may be advantageous to arrange
with the network administrator for an entry on the BOOTP database, so that the host can boot quickly on that network rather than cycling
through the list of old leases.
NOTES
You must have the Berkeley Packet Filter (BPF) configured in your kernel. The dhclient utility requires at least one /dev/bpf* device for
each broadcast network interface that is attached to your system. See bpf(4) for more information.
FILES
/etc/dhclient.conf DHCP client configuration file
/var/db/dhclient.leases.IFNAME database of acquired leases
SEE ALSO dhclient.conf(5), dhclient.leases(5), dhclient-script(8)AUTHORS
The dhclient utility was written by Ted Lemon <mellon@fugue.com> and Elliot Poger <elliot@poger.com>.
The current implementation was reworked by Henning Brauer <henning@openbsd.org>.
BSD October 13, 2011 BSD