Use the DNS name server. This service type is useful only with the hosts entry. The name servers queried are still determined by the standard resolv.conf file. While these versions normally can't interpret older NIS entries in passwd and group files, compat option allows them to work with those formats. The corresponding NIS map name is used for that file.
More entries are likely to be added.
Example 13-2 shows a more complete example that introduces another feature of nsswitch.conf . That is, the NIS client will continue searching the local files only if calls to the NIS and DNS servers fail for some other reason. The local files will then be used only at boot time and as a backup when the NIS server is down. GNU libc provides some other actions that are described in the nsswitch manpage.