DHCP Explained

Dynamic Host Configuration Protocol (DHCP) can be a great help in building an intranet as it greatly simplifies the task of defining an addressing system and setting up the correct address on each workstation and server.

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With the growth of the Internet, TCP/ IP has now become a must- have protocol for most computer networks. It provides a single network protocol that is supported by almost every type of computer system, a plethora of applications 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 intranet.

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 peripheral on the network. This can entail an immense amount of system administration work.

DHCP stands for Dynamic Host Configuration Protocol, and is used to centrally allocate and manage TCP/ IP configurations of client nodes. If 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 administering 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 DHCP terminology.

* Not only are the TCP/ IP addresses handed out, so are all the related configuration settings like the subnet mask, default router, DNS server, 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 reconfigure 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 addresses 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 clients, which will be discussed later.

A DHCP server is included in Windows NT Server 3.51 and4. 0. Although this article is concentrating on NT Server, DHCP isn’t a Microsoft standard and is available from other vendors for NT (such as MetaInfo), and on other platforms. For more information see the DHCP FAQ, which is discussed below.

DHCP Tutorial page 2