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Why DHCP?

Manually assigning IP addresses to a network is time consuming as you need to record which address you have used and which computer that you have assigned it to. This is suitable for a one-room computer room as you can quickly check which addresses are available. For a large or widespread network, you should automatically assign IP addresses using DHCP. This assigns dynamic IP addresses to each computer when they ask for one when starting up from a set range allocated by the administrator.

For example, enabling Internet Connection Sharing on a Windows 98 system allows the system to act as a DHCP server and allocates addresses to all other computer on that network whose TCP/IP properties are set to obtain an IP address automatically.

Addresses assigned this way are renewed at intervals set by the DHCP server. As these might change each time they are renewed and most of the shared resources use the name of the computer, we need to keep track of which computer has which IP address. Windows Internet Name Service (WINS) does this by creating a distributed database that contains all currently available computers names and IP addresses. When the system is looking for a particular computer it will look at this database first and uses the IP address that it finds. If it cannot find the computer in the database it will check each IP address it finds on the network until it finds the computer or has checked all addresses. If it does find the computer it will update the database.

Next: Other TCP/IP Services