D.2. The dhcpd Command
of the dhcpd
dhcpd [-p port] [-f] [-d] [-cf config-file] [-lf lease-file] [if0 [ifn]]
dhcpd usually is run without any command-line
arguments. Most of the arguments are used only when testing and
debugging. Two of the command-line arguments handle special
Runs dhcpd in foreground mode. By default,
dhcpd runs as a background daemon process. Use
-f when dhcpd is started from
inittab on a System V Unix system.
- if0 [...ifn]
Lists the interfaces on which dhcpd should listen
for BOOTREQUEST packets. This is a whitespace-separated list of
interface names. For example, dhcpd ec0
ec1 wd0 tells dhcpd to listen
to interfaces ec0, ec1, and wd0. Normally this argument is not
required. In most cases dhcpd locates all
installed interfaces and eliminates the no-broadcast interfaces
automatically. Use this argument only if it appears that
dhcpd is failing to locate the correct interfaces.
All of the remaining command-line arguments are used for debugging or
- -p port
Causes dhcpd to listen to a nonstandard port. The
well-known port for DHCP is 67. Changing it means that clients cannot
talk to the server. On rare occasions this is done during testing.
Routes error messages to stderr. Normally error messages are written
via syslog with facility set to DAEMON.
- -cf config-file
Causes dhcpd to read the configuration from the
file identified by config-file instead of
from dhcpd.conf. Use this only to test a new
configuration before it is installed in
dhcpd.conf. Use the standard file for
- -lf lease-file
Causes dhcpd to write the address lease
information to the file identified by
lease-file instead of to
dhcpd.leases. Use this only for testing.
Changing the name of the lease file could cause dynamic addresses to
be misallocated. Use this argument with caution.
Kill the dhcpd daemon with the SIGTERM signal. The
process ID (PID) of the dhcpd daemon is found in
the /var/run/dhcpd.pid file. For example:
# kill -TERM 'cat /var/run/dhcpd.pid'
dhcpd uses three files. It writes its PID to
/var/run/dhcpd.pid, maintains a record of
dynamic address leases in /var/db/dhcpd.leases,
and reads its configuration from
/etc/dhcpd.conf. These last two files are
created by you. Create an empty lease file before you run
dhcpd the first time, e.g., touch
/var/db/dhcpd.leases. Create a configuration and store it
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