The Problem of Managing Network Information
In the 1970s, when computers were expensive and networks consisted of a few nodes, administering network information for a few nodes was manageable and a centralized system was not needed. As computers became cheaper and networks grew larger, it became increasingly more difficult to maintain separate copies of network configurations on every individual system.
For example, whenever a new user was added to the network, the following files would need to be updated on every existing system:
| File | Sample entry | Information |
|---|---|---|
| /etc/passwd | numiri:x:37:4:Sebastian Nguyen:/home/numiri | user name, home directory, ... |
| /etc/shadow | numiri:1AD3ioUMlkj234k: | encrypted password |
Likewise /etc/group would have needed updating every time a new group was added and /etc/hosts would have needed updating every time a new computer was added to the network.
If a new user with a new system is added to a network of 20 existing systems, the UNIX administrator would need to modify 5 files on 21 machines, or 105 files in all. With NIS+, adding user and machines to the network only requires changes to the NIS+ server's maps and the new host’s /etc/nsswitch.conf needs to point to the NIS+ server. When a user logs into any other machine, that host (the NIS+ client), knowing who the NIS+ server is, queries it for the username and password to identify and authenticate the user.
NIS+ also manages several other types of data: NFS mounts (auto_master, auto_home), network booting and other parameters (bootparams, ethers, netmasks, netgroup, networks, protocols, rpc, services), security access (cred), aliases, and timezone.
An installation of NIS+ comes with such table structures predefined. There are facilities available to create other tables as needed.
Read more about this topic: NIS+
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