Portmaps
sudo apt-get install -y portmap
Portmap is a part of ONC RPC (Open Network Computing Remote Procedure) collection of software for implementing remote procedure calls between Computer Programs. It is widely used by NFS (Network File System) and NIS. Portmap is a server that converts RPC program number to DARPA protocol port number. It must be used in order to make RPC calls.
Network Infomation Service (NIS)
sudo apt-get install -y nis
NIS is a client server directory service provider for distributing system configuration data as user and host name between computers on comptuer network. SUN Microsystem developed the NIS; the technology is licensed to virutually all other UNIX vendors. NIS maintains and distrubutes a central directory of user and group information, hostnames, email aliaases and other text based table of information in a computer network. NIS sevice provides information that hast o be know throughout the network, to all machines on the network.
It was previously named as Sun Yellow Pages but since Yellow Page was already used they had to change their name.
NIS+ is just a steriod version of NIS, which adds more security to the NIS service.
Autofs
sudo apt-get install -y autofs
AutoFS controls the operation of the automount deamons on the linux system. Usually autofs is invoked at system boot time with the start parameter and at the shutdown time with the stop parameter. Autofs will consult with configuation file /etc/auto.master to find mount point on the system.
Network File System (Protocol)
Network File System (NFS) is a network file system protocol origiannly developed by Sun Microsystem 1984 allowing a user on a client computer to access files over network in a manner similar to how local storage is accessed. NFS, like many other protocols, builds on the ONC RPC. NFS is an open standard / protocol defined in RPC allowing anyone to implement the protocol.
Source:http://aayushtuladhar.wordpress.com/2012/02/10/networking-terminologies/