WINS service Introduction

Wins is short for Windows Internet Name Server (Windows Internet Name Service. Wins provides name registration, update, release, and Conversion Services for NetBIOS names. These services allow the WINS server to maintain a dynamic database that links NetBIOS names to IP addresses, greatly reducing the network traffic burden.

I. Why do we need the WINS service?

By default, the NetBIOS name of each computer on the network is updated through broadcast. That is to say, if there are n computers on the network, so every computer needs to broadcast n-1 times. For small networks, this does not seem to affect network traffic, but when large networks are concerned, the network burden is increased. Therefore, wins is especially important for large and medium-sized enterprises.

Ii. How wins works

As mentioned above, the WINS server provides the client with the following basic services:

1. Name Registration

Name Registration is the process in which the client obtains information from the WINS server. In the WINS service, name registration is dynamic.

When a client starts, it sends a name registration information (including the Client IP address and computer name) to the configured WINS server. If the WINS server is running, if no other client computer has registered the same name, the server returns a message (including the name registration period-TTL) to the client computer ).

Like an IP address, each computer must have a unique computer name. Otherwise, communication will fail. If the name has been registered by another computer, the WINS service will verify that the name is in use. If the name is in use, registration fails (a message of Negative confirmation is returned); otherwise, registration can continue.

2. Name update

Because the client is assigned a TTL (storage period), all its registration has a certain period of time. After this period, the WINS server will delete the registration information of this name from the database. The process is as follows:

(1 ). after 1/8 of the current period, the client continuously tries to update its name registration. If no response is received, the WINS client repeats the update every two minutes until the current period has passed half.

(2) When the current period is over half, the WINS client will try to update its lease with the secondary WINS server. The process is the same as that of the preferred WINS server.

(3) If the client still fails after half of the time, the client returns to its preferred WINS server.

In this process, whether it is the preferred or secondary WINS server, once the name registration is successful, the name registration of the WINS client will be provided with a new TTL value.

3. Release the name

During the normal shutdown of the client, the WINS client sends a name release request to the WINS server to release the IP address and NetBIOS name mapped to the WINS Server database. After receiving the release request, the WINS server verifies whether the IP address and NetBIOS name exist in its database. If yes, the server can be released normally, otherwise, an error occurs (the WINS server sends a negative response to the WINS client ).

If the computer is not properly shut down, the WINS server will not know that its name has been released, and the name will not expire until the WINS name registration record expires.

4. name resolution

When the client needs the WINS server to resolve the name in many network operations, for example, when using shared files from other computers on the network, you need to specify two things to get shared files: the system name and the shared name must be converted to an IP address.

The name resolution process is as follows:

(1) When the client computer wants to convert a name, it first checks the local NetBIOS name cache.

(2 ). if the name is not in the local NetBIOS name cache, a name is sent to the preferred WINS Server (sent every 15 seconds, three times in total). If the request fails, the same request is sent to the selected wins.

(3) If all of them fail, you can use other methods for name resolution (such as local broadcast, LmHosts file and hosts file, or DNS.

Iii. Requirements for WINS servers and clients

1. Microsoft's requirements for Servers

(1). At least one preferred WINS server and one secondary WINS server are provided to provide fault tolerance.

(2) a wins server can process nearly 1500 name registration and about 4500 name queries every minute. Therefore, we strongly recommend that you use a preferred server and a secondary WINS server to drive up to 10000 clients.

(3) If the WINS server and the client are not on the same subnet, the performance of the router must be taken into account.

2. Client Requirements

Almost all Microsoft clients supporting network interconnection can be wins clients. The following lists clients that can work with wins:

* Windows NT Server 3.5x, 4.0

* Windows NT Workstation 3.5x, 4.0

* Windows 9x/ME/2000

* Windows for workgroups with TCP/IP-32

* Microsoft network client 3.0 for MS-DOS

* LAN Manager 2.2C for MS-DOS

DOS-based clients can also use the WINS server for name resolution, but you must add static entries to the WINS server.

Article entry: dnbm responsible editor: dnbm