When the DHCP
server is started for the first time, it fails unless the
dhcpd.leases file exists. Use the command touch
/var/lib/dhcpd/dhcpd.leases to
create the file if it does not exist.
If the same
server is also running BIND as a DNS server, this step is not necessary, as
starting the
named service automatically checks for a dhcpd.leases file.
To start the
DHCP service, use the command
/sbin/service dhcpd start.
To stop the DHCP server, use the command /sbin/service dhcpd stop.
By default, the
DHCP service does not start at boot time. To configure the daemon to start automatically
at boot time.
If more than one
network interface is attached to the system, but the DHCP server should only be
started on one of the interfaces, configure the DHCP server to start only on
that device. In
/etc/sysconfig/dhcpd, add
the name of the interface to the list of DHCPDARGS:# Command line options here
DHCPDARGS=eth0
This is useful
for a firewall machine with two network cards. One network card can be configured
as a DHCP client to retrieve an IP address to the Internet. The other network card
can be used as a DHCP server for the internal network behind the firewall. Specifying
only the network card connected to the internal network makes the system more
secure because users can not connect to the daemon via the Internet.
Other command
line options that can be
specified in
/etc/sysconfig/dhcpd include:-p<portnum>— Specifies the UDP port number on whichdhcpdshould listen. The default is port 67. The DHCP server transmits responses to the DHCP clients at a port number one greater than the UDP port specified. For example, if the default port 67 is used, the server listens on port 67 for requests and responses to the client on port 68. If a port is specified here and the DHCP relay agent is used, the same port on which the DHCP relay agent should listen must be specified.-f— Runs the daemon as a foreground process. This is mostly used for debugging.-d— Logs the DHCP server daemon to the standard error descriptor. This is mostly used for debugging. If this is not specified, the log is written to/var/log/messages.-cf<filename>— Specifies the location of the configuration file. The default location is/etc/dhcp/dhcpd.conf.-lf<filename>— Specifies the location of the lease database file. If a lease database file already exists, it is very important that the same file be used every time the DHCP server is started. It is strongly recommended that this option only be used for debugging purposes on non-production machines. The default location is/var/lib/dhcpd/dhcpd.leases.-q— Do not print the entire copyright message when starting the daemon.
