With the growth of the In-
ternet, TCP/IP has now be-
come a must-have protocol
for most computer networks. It pro-
vides a single network protocol that is
supported by almost every type of
computer system, a plethora of appli-
cations that use it, and it is well suited
to both large and small networks. It’s
also essential if you wish to set up an
The downside of TCP/IP is that,
unlike protocols such as IPX, it needs
addresses and configuration settings
to be defined on each computer or pe-
ripheral on the network. This can entail
an immense amount of system admini-
DHCP stands for Dynamic Host
Configuration Protocol, and is used to
centrally allocate and manage TCP/IP
configurations of client nodes.
you’ve got more than a handful of
computers to manage, then DHCP can
help to save a great deal of time and
trouble in setting up and administer-
ing a TCP/IP network. DHCP offers
the following features:
● It allows you to define “pools” of
TCP/IP addresses, which are then
allocated to client PCs by the server.
These pools are called scopes in
● Not only are the TCP/IP addresses
handed out, so are all the related
configuration settings like the sub-
net mask, default router, DNS serv-
that are required to make
TCP/IP work correctly.
● DHCP works across most TCP/IP
routers and allocates IPs according
to the subnet the request came from.
This means you won’t need to re-
configure a PC that is moved from
one subnet to another.
● Addresses can be leased for periods
of time - so an IP address that is not
used for the duration of the lease is
put back into the unallocated pool.
This helps recover TCP/IP ad-
dresses that are no longer used.
What Do I Need?
To use DHCP you need a DHCP
server (to allocate the addresses and
maintain a database) and DHCP cli-
ents, which will be discussed later.
A DHCP server is included in Win-
dows NT Server 3.51 and 4.0. Although
this article is concentrating on NT
Server, DHCP isn’t a Microsoft stand-
ard and is available from other ven-