Linux Network Administrator's Guide, Second Edition

Choosing the Right Maps

Having made sure you can reach the NIS server, you have to decide which configuration files to replace or augment with NIS maps. Commonly, you will want to use NIS maps for the host and password lookup functions. The former is especially useful if you do not have the BIND name service. The password lookup lets all users log into their accounts from any system in the NIS domain; this usually goes along with sharing a central /home directory among all hosts via NFS. The password map is explained detail in the next section.

Other maps, like services.byname, don’t provide such dramatic gains, but do save you some editing work. The services.byname map is valuable if you install any network applications that use a service name not in the standard services file.

Generally, you want to have some choice of when a lookup function uses the local files, when it queries the NIS server, and when it uses other servers such as DNS. GNU libc allows you to configure the order in which a function accesses these services. This is controlled through the /etc/nsswitch.conf file, which stands for Name Service Switch, but of course isn’t limited to the name service. For any of the data lookup functions supported by GNU libc, the file contains a line naming the services to use.

The right order of services depends on the type of data each service is offering. It is unlikely that the services.byname map will contain entries differing from those in the local services file; it will ...