Configure a notebook for multiple networks


Q I have P133 laptop with 40MB RAM and Windows 95. I travel a lot between three different locations, each with its own network, using a different network client. I was wondering if there is a way to set up the computer so that the different IP addresses, computer names, gateways etc are automatically installed when I log in as a different user, rather than going through the whole process manually each time.

û Rebecca Webb

A Because networks may be set up in a complex and highly individual manner I am going to concentrate on TCP/IP networking, which is the protocol used for an Internet connection and is often used now for local area networks. It is also the one type of network that can be easily set up to provide all settings automatically.

When specifying a connection to the Internet, three settings are often required: the IP address, the default gateway and DNS. In addition, for many LANs using TCP/IP you need to specify a WINS server.

The default gateway is the route that your computer will use to connect to the outside world (eg the Internet). This option is arguably the least important because even if the wrong gateway is specified, a substitute will often be found.

The DNS (Domain Name Server) matches Internet server names with the appropriate IP addresses, which your computer then uses to make the connection. With DNS, you can specify multiple servers so you can put the servers for all the networks in your DNS list.

WINS is used to allow you to browse a LAN using simple names rather than having to specify a full Internet name. If you are only using TCP/IP for an Internet connection you donÆt need to specify a WINS server.

The sticking point will be the IP address. Each computer on the Internet needs to have a unique IP number. Most properly configured TCP/IP networks will not allow you to use anything but the appropriate IP number for the network.

It is possible to set up a network to provide the appropriate addressing information to a client machine automatically when you first connect to the network. This is done using a DHCP server. A DHCP server comes bundled with Windows NT server and is available for every flavour of Unix as well as Novell NetWare. Your problem is getting the administrators of your three networks all to agree to use DHCP servers!

If you have to change settings manually, one way to speed this up is to use a program such as IPSwitcher (available on our cover CD and from www.active4.com). This allows you to set up several alternative configurations and to switch to them easily. You still have to reboot for the settings to take effect.

û Roy Chambers


Category:networking
Issue: July 1998

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