An NIS record has a maximum size of 1024 bytes. This limitation applies to all NIS map files. For example, a list of users in a group can contain a maximum of 1024 characters in single-byte character set file format. NIS cannot operate correctly with map files that exceed this maximum. The most commonly used maps have nicknames that some commands can translate into map names.
Clients use the ypservers map to find the nearest available server.
The master server refers to it to determine the names of the slave servers that need to obtain updated copies of the NIS maps. Information about specifying the input to the ypservers map is discussed in Configuring the NIS Master Server and in Adding a New NIS Slave Server . Rather, it is strictly an NIS file that resides on the master server. NIS provides these maps for authentication purposes during login, remote login, remote mount, and remote shell processes. Creating Maps NIS maps are created by the makedbm command, converting text files into DBM format files.