Manage Large Number of Machines
Editing /etc/hosts over and over on each machine grows exponentially boring. Having one machine as name server on network means only one point of adding/changing/deleting machine names/IPs, etc..
Netbooting: JumpStart/PXE Boot/bootp servers
Authentication: NIS/Kerberos/LDAP/RADIUS/PAM/OpenSSH keys, etc..
Directory services are based on X.500 specification.
OpenLDAP on IRIX
OpenSSH on IRIX
NIS on IRIX
Resource sharing: SAMBA, NFS, etc...
Inconsistent user ids (uid) on remote shares.