6. Name services

There are 4 primary naming services within Solaris System V UNIX: DNS, NIS, NIS+, and files. Humans like names better than numbers, while computers like numbers. A naming service translates a word or phrase (i.e. mycomputer) to something the computer understands (i.e. 192.168.0.23). Look at the following to see an example:

To show hosts on a machine look in /etc/inet/hosts. This file holds information on other hosts on your network. Output may look like this:
127.0.0.1 localhost
192.168.0.24 myserver
192.168.0.23 mycomputer

To add hosts to this file, use the vi editor or type admintool (while logged in as root)

DNS (Domain Naming Service) is a global naming service. Characteristics of DNS

• Hosts table
• Single database worldwide
• External to Internet
• This is applicable to the whole planet
• Runs the Internet

NIS and NIS+ (Network Information Services) is a way around DNS. Characteristics of NIS and NIS+:

• Supports different database
• Internal to company
• NIS is usually used on a department or small company scale
• NIS+ is used mainly for large company wide networks and is very secure

Files is a local naming system. Characteristics of Files:

• Supports any database
• Internal to host

A. DNS

To have yourself as a DNS client edit /etc/resolv.conf. You will need the following info: (this is what the file will look like)
Domain mynetwork.com (this is where you put the name of your domain)
mycomputer 192.168.0.23 (This is where you put your nameserver information)

There is only one DNS domain for the world ( . or the nameless root) it is nameless and you put a space and dot.

There are two types of DNS

1. Lookup (or Bind) – which goes to a caching server to look for the IP for you
2. Database – which has primary and secondary servers that will just hold the top level domain information.

To create a lookup (bind), edit the /etc/resolv.conf (which controls how DNS works) file. It will hold the following info, and will look like the listing on the below:
domain [what domain you are in, i.e. mydomain.com]
nameserver [caching server the ISP will give you. You could have multiple nameserver entries]

After you edit the /etc/resolv.conf file, you will test DNS by using nslookup, then you go to a “>” prompt, and then type [the world wide web address] (i.e. http://home.earthlink.net/~pandsl). If it works then your DNS works.

To allow caching edit /etc/nsswitch.conf and puts the following entry: host: files dns

B. NIS+

To have yourself as a NIS+ client, use the following command: nisclient –i –h [nis plus server] –a [IP address] –d [nis plus domain]

C. NIS

To have yourself as a NIS client, use the following command: ypinit –c

Then for all three use the vi editor to modify /etc/nsswitch.conf (tells where records go to find info)

• Passwd: files nisplus (add to have UNIX go to nisplus to find password)
• Group: files
• Hosts: files dns nisplus

-or-

• Hosts: nisplus dns [notfound=retrn] files

* order is very important. The not found will keep your system from freezing.

Client setup

1. For NIS client you type ypinit –c (-c is for client)
2. For NIS+ client type /usr/lib/nis/nisclient –l –h [masterserver.domain.com] –a [ ip of –h option] –d [domain.topleveldomain]. You must already have credentials on the master server which include “secure rpc password”, usually NIS+ to start, and you must also have the root password of the client.

Name Services

• Data is stored on server (with automount)
• Client uses data
• consistent on both

A common problem is to make sure that /etc/hosts is linked to /etc/inet/host, this will allow changes on 1 machine to go to many automatically. In /etc/nsswitch.conf – name service info will look like this:
Passwd: files

Service where to go for that info (could be nis, nis+ or dns or all)

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