On the module's main page, click the NIS Client icon. This will take you to a form for entering the domain name and NIS server IP addresses.

In the NIS domain field, enter the name of your network's NIS domain.

If you do not know the IP address of an NIS server, set the NIS servers option to Find by broadcast. This will work only if the server is on the same LAN as your system—if not, the broadcast will not be able to reach it.

If you do know the address of an NIS server, select the Listed below option and enter all the master and slave server addresses into the text box. The more you enter the better, because your system will try to query each of them in turn when NIS is enabled. However, it is best to enter the nearest server first so that a more distant and thus slower server is not always queried.

Click the Save and Apply button to have your settings saved and immediately activated. If your system cannot contact a server for the NIS domain, an error message will be displayed—otherwise, the browser will return to the module's main page.

Now that you are connected to an NIS server, you must configure the system to actually query it for users, groups, and other information. To do this, click on the Client Services icon which will take you to the form shown in Figure 17.1.

Each row of the client services form controls what your system will query when looking something up for a particular service. For each, you can select several sources that will be checked in order until one finds a match. The available sources are:

Files Local configuration files, such as /etc/passwd or /etc/hosts.

NIS This NIS server that your system is currently connected to.

NIS+ The NIS+ server that your system is connected to. Configuring NIS+ is not supported by Webmin.

NIS and Files This option only works for the UNIX users and UNIX groups services. If chosen, special lines in /etc/passwd and /etc/group starting with + or – can be used to indicate that some or all NIS users should be included. This is actually more flexible than just choosing the NIS source, as special + and – lines can be used to bring in only some users and groups, or change the attributes of those that are included.

DNS This option makes sense only for the Host addresses source. It tells the system to query a DNS server when looking up hostnames, which is almost always what you want to do.

Typically, you should set each of the services for which you want to use NIS (such as UNIX users and UNIX groups) to Files and NIS. Everything else should be left set to just Files, or in the case of Host addresses just Files and DNS. Your system will then look in the local system configuration file first (such as /etc/passwd) and then query the NIS server.

When done, click the Save button. Your changes will take effect immediately in all programs, and any NIS users should be able to log in just as local users would.

On the main page of the module, click the NIS Client icon to go to the client options page.

Set the NIS domain field to None (NIS disabled).

Click the Save and Apply button. The system will no longer use NIS to look up any information, and will not connect at boot time. Any services that are configured to use an NIS source on the Client Services page will simply skip that source, and most likely use only local files instead.