Sams Teach Yourself MCSE Windows NT Server 4 in 14 Days
(Publisher: Macmillan Computer Publishing)
Author(s): David Schaer, et al
ISBN: 0672311283
Publication Date: 12/15/97

4.  Choose OK. This brings you back to the Static Mappings window, but you should now see your new entry in the mappings window (see Figure 11.23).

Figure 11.23.  Static mappings have been added to the WINS database.

Note that although you added only one static mapping, three now show up in the window. In actuality, each service running on a WINS client requires a NetBIOS name of its own. NetBIOS names are actually 16 characters. The first 15 characters are the familiar name of the computer and the 16th, a hexadecimal number, represents the service. In this example, the Workstation [00h], Messenger [03h], and Server [20h] services each have their own NetBIOS name.

By using the Static Mappings window in Figure 11.23, you may also select Import Mappings to import an existing LMHOSTS file into the WINS database.

Viewing and Backing Up the WINS Database

You can view the WINS database at any time from the WINS Manager. Select Show Database from the Mappings menu to bring up the Show Database window, shown in Figure 11.24.

This dialog box enables you to view all mappings in the WINS database or only the mapping owned by a particular server based on various sort options. You also can delete a server from the database by selecting the server and then choosing Delete Owner.

To back up the WINS database, you must first choose a backup directory. To do this, in WINS Manager select Back Up Database from the Mappings menu. After you have done this, the database will be backed up automatically every 24 hours. You can restore the database by using one of two methods. The first is to simply stop and restart the WINS Server service. This automatically restores a corrupted database. The second method is to choose Restore Database from the Mappings menu in WINS Manager.

Figure 11.24.  Viewing a WINS database using WINS Manager.

11.4.4. WINS Optimization

The traffic that occurs between the WINS server and its clients consists of name registrations, renewals, and releases as well as name resolution. The two areas that can be optimized are the frequency of name renewals and the number of names per host that are registered.

When a name is registered with a WINS server, a time to live (TTL) is assigned to it. Although the size of the renewal frames and the resulting network traffic is fairly small, this traffic can be further reduced by lengthening the TTL. Name renewal then occurs at one-half of the new TTL. This helps reduce network traffic only if the host does not shut down during this period.

The other main area of optimization is to reduce the number of names a host registers and must periodically renew. You can do so by stopping any unnecessary services. For example, if the host does not share resources over the network, stopping the server service prevents the host from having to register or renew this service. Stopping any unnecessary services is also wise from a security aspect.

After a NetBIOS name as been resolved, it is placed in the NetBIOS name cache. This cache is checked before sending a request to the WINS server. The default length of time that names remain in the cache is 10 minutes and is configured in the registry. By lengthening the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetBT\Parameters\CacheTimeout to a higher value, those most frequently accessed names are resolved from the cache rather than by requesting the resolution from the WINS server, thereby reducing network traffic.

The other method of reducing NetBIOS name resolution from the WINS server is by using an LMHOSTS file. By preloading the names of domain controllers or other frequently accessed servers, the amount of network traffic for name resolution is also reduced.

When optimizing push/pull partners for WINS, you should take into consideration the type of link between the two servers. If your WINS servers are local to each other, configure pull requests for every 30 minutes but extend this to every six hours if the replication is occurring over a slow WAN link.

Push notifications default to 20 changes in the database. If this replication occurs across a WAN link, increasing this number results in a decrease in network traffic. Although this decreases network load, it may lead to using an out-of-date database for name resolution.