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Lesson 7 Starting the name server process
Objective Start and troubleshoot the name server process.

Starting the Name Server Process

To start the name server process, you need only type /usr/sbin/named on Linux, or /usr/sbin/in.named on Solaris.
After you have started the name server, use ps in combination with tail and grep to view the messages file:

tail /var/log/messages | grep named
Using this command, you can see any error or success messages generated by named. If you receive many error messages, you may need to use the -n option to specify more lines with tail.

Troubleshooting

If you find errors, first look for missing terminating periods in the zone files. This is the primary cause for problems with the named process. Every fully qualified name that occurs must have a terminating period. You should also make sure that the /etc/named.boot or named.conf file lists the proper file names. If you make any changes to either file, issue a kill -HUP signal for the named PID.
If your machine functions as a secondary server, check the /var/named directory. You should see that new zone files have appeared in that server’s /var/named directory. These files have appeared as the result of a zone transfer. If you do not see them, check the /var/log/messages directory for errors.

Run nslookup

The nslookup program is the primary tool to use for troubleshooting DNS. Use the ls command to list your domain, then issue the set type=SOA command to make sure that you can retrieve the SOA record. Then, you can instruct nslookup to query the server on your own system:
server your_own_ip_address
Make sure that you can look up host names using your own server, as well as the secondary server.

nslookup

nslookup works similarly to dig but is deprecated in Linux. Using it requires more work, but you should be familiar with it because Microsoft Windows still uses it as its primary lookup tool. nslookup queries Internet domain nameservers in two modes: interactive and noninteractive. The interactive mode allows you to query nameservers for information about various hosts and domains, or to print a list of hosts in a domain. The noninteractive mode simply prints the name and requested information for a host or domain. For example, you could run the following lookup to find some information about Google's server:
# nslookup ns1.google.com
Server: 68.94.156.1
Address: 68.94.156.1#53
Non-authoritative answer:
Name: ns1.google.com
Address: 216.239.32.10

In interactive mode, nslookup provides a prompt where you can execute commands. For example:
# nslookup
>
From the prompt you can do simple lookups, such as on an IP address:
> 70.253.158.42
Server: 172.30.1.2
Address: 172.30.1.2#53

Non-authoritative answer:
42.158.253.70.in-addr.arpa name = adsl-70-253-158-42.dsl.rcsntx.swbell.net.
Authoritative answers can be found from:
158.253.70.in-addr.arpa nameserver = ns1.swbell.net.
158.253.70.in-addr.arpa nameserver = ns2.swbell.net.
>
You can also execute several commands, including lserver (which uses your local server to do a lookup), server (which uses another server to do a lookup), and host. The lserver command produces output like the following:
> lserver google.com
Default server: google.com

Start name Server Process

Click the Exercise link below to start the name server process. The process is the same for Linux and Solaris.
Start name Server Process