Microsoft Networking Over IP

What is WINS?

WINS is an IP name server designed specifically for the Windows Networking environment. It has several benefits over regular DNS when used by Windows machines.

• WINS is dynamic - client machines register themselves when they start up
• WINS can register multiple NetBEUI services at a single IP address
• WINS can register Microsoft domains

Client machines must be configured with one or more WINS server addresses in order to register themselves and perform WINS name lookups. This configuration is done in the TCP/IP protocol section of the client machine's Windows network control panel.

What is a browser?

A browser (perhaps more appropriately called a browse server) is a computer which answers Microsoft Network browse requests from workstations which are within its broadcast area. These requests are answered with a list of domains and/or workgroups, and services.

Browse requests are only sent as IP broadcasts (along with other non-IP requests). This means that for browsing to work, every broadcast area must have a browser running.

Browser software comes standard on Windows NT Server and Workstation, and is available from Microsoft for Windows 95. Browsers automatically decide between themselves which machine will actually answer broadcast browse requests within a broadcast area. The machine selected is known as the Master Browser.

What do you mean by broadcast area?

Either a single physical network segment, with no intervening routers, or multiple segments whose routers perform reciprocal UDP relays of the appropriate NetBEUI packet types.

Note: If the relays are not reciprocal, the browsers within the broadcast area become confused because they can't see each other.

What is the difference between a name lookup and browsing?

Name lookups (i.e. Find Computer) are available to any machine that can reach a configured WINS server. A successful name lookup is enough to be able to log into a server, but will not provide information about other resources within the same domain/workgroup.

Browsing (i.e. Network Neighborhood) is only available to machines which have a browser running within their broadcast area. Name lookups alone will not allow browsing to work - there must be a browser running in the broadcast area.

What is a Microsoft workgroup?

A workgroup is a logical grouping of two or more machines which share a common configured 'workgroup name' and are in the same broadcast area.

So, multiple workgroups can exist on a single subnet, but multiple subnets cannot contain a single workgroup unless relays are set into intervening routers.

Can WINS be used to span a workgroup across multiple subnets?

No. WINS alone will only provide name lookup service (using Find Computer from the Network Neighborhood or the Find menu).

What is a Microsoft domain?

A domain is a logical group of two or more machines (typically many more) which, with the help of WINS or static LMHOSTS files, can span multiple IP subnets which are not part of the same broadcast area.

What is required to set up a domain?

In order to set up a domain, you must have a Windows NT Server configured as a Primary Domain Controller (PDC). This configuration must be elected when installing/updating the server software. PDCs automatically become the 'Domain Master' browser for their domain, keeping a list of all resources within the domain.

How does a domain span multiple subnets using WINS?

WINS allows domains and their PDCs to be registered. If a browser is configured to be part of a domain, and to access a WINS server which knows about that domain, the browser will perform a reverse lookup to get the PDC address and will then trade resource information with the Domain Master Browser running on the PDC.

Subsequent browse requests will be answered with the complete list of resources in the domain.

What is the difference between a domain login and a workgroup login?

A domain login provides domain-wide authentication of the computer which is logging in. This means the user only needs to go through one login prompt and can then connect to multiple domain resources without additional prompts.

A workgroup login is performed on a resource by resource basis.