26
DHCP
The purpose of the Dynamic Host Conguration Protocol (DHCP) is to assign network
settings centrally (from a server) rather than conguring them locally on each and every
workstation. A host congured to use DHCP does not have control over its own static
address. It is enabled to congure itself completely and automatically according to di-
rections from the server. If you use the NetworkManager on the client side, you do not
need to congure the client at all. This is useful if you have changing environments
and only one interface active at a time. Never use NetworkManager on a machine that
runs a DHCP server.
One way to congure a DHCP server is to identify each client using the hardware address
of its network card (which should be xed in most cases), then supply that client with
identical settings each time it connects to the server. DHCP can also be congured to
assign addresses to each relevant client dynamically from an address pool set up for
this purpose. In the latter case, the DHCP server tries to assign the same address to the
client each time it receives a request, even over extended periods. This works only if
the network does not have more clients than addresses.
DHCP makes life easier for system administrators. Any changes, even bigger ones, re-
lated to addresses and the network conguration in general can be implemented centrally
by editing the server's conguration le. This is much more convenient than recong-
uring numerous workstations. It is also much easier to integrate machines, particularly
new machines, into the network, because they can be given an IP address from the pool.
Retrieving the appropriate network settings from a DHCP server is especially useful
in case of laptops regularly used in different networks.
In this chapter, the DHCP server will run in the same subnet as the workstations,
192.168.2.0/24 with 192.168.2.1 as gateway. It has the xed IP address 192.168.2.254
DHCP 447
