NIS
Network Information Services. A naming service that allows resources to be
easily added, deleted, or relocated. Formerly called Yellow Pages (yp), NIS is a
de facto Unix standard. NIS+ is a redesigned NIS for Solaris 2.0 products. The combination
of TCP/IP, NFS, and NIS comprise the primary networking components of Unix.
NIS contains data, such as host files, password files, and e-mail aliases for
entire networks. It allows a remote user to obtain copies of the NIS password
map information. An attacker who possesses the NIS domain name (often set up as
a derivative of the public domain name) can steal information helpful in
guessing passwords and gaining unauthorized access.