Difference between revisions of "Dns Management"

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{{outdated|[[Dns1]] no longer exists; the current nameserver is [[Talos]], which has the same static IP address. The zone files and nameserver configuration is in <code>/etc/bind/</code>. That aside, all the other operations/practices are accurate.}}
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==Introduction==
 
==Introduction==
 
A DNS server manages name resolution of computers on a subdomain.  For example, going to '''docs.cslabs.clarkson.edu''' you are using clarkson.edu's DNS server to find the ip address of '''cslabs'''. This would be the CSLabs' DNS server.  Now we use the CSLabs' DNS server to find the ip address of '''docs'''.
 
A DNS server manages name resolution of computers on a subdomain.  For example, going to '''docs.cslabs.clarkson.edu''' you are using clarkson.edu's DNS server to find the ip address of '''cslabs'''. This would be the CSLabs' DNS server.  Now we use the CSLabs' DNS server to find the ip address of '''docs'''.

Latest revision as of 18:10, 19 February 2018


Introduction

A DNS server manages name resolution of computers on a subdomain. For example, going to docs.cslabs.clarkson.edu you are using clarkson.edu's DNS server to find the ip address of cslabs. This would be the CSLabs' DNS server. Now we use the CSLabs' DNS server to find the ip address of docs.

Where are the files?

The files you need to edit are in /var/named/ on Dns1. They link to corresponding files in /var/named/chroot/var/named/. You need to be root to edit these files.

What do the files mean?

cslabs.clarkson.edu.zone

The purpose of this file is to look up ip addresses from a name.

game            IN      A       128.153.145.36
tremulous       IN      CNAME   game

This snippet of the file shows that game.cslabs should be resolved 128.153.145.36. It then goes on to specify that tremulous.cslabs should resolve to the same address as game.cslabs.

145.153.128.in-addr.arpa

The purpose of this file is to look up the name from a ip address.

36       IN      PTR     game.cslabs.clarkson.edu.

This snippet shows that 128.153.145.36 is game.cslabs.clarkson.edu.

All

Changing the serial number lets Dns2 know that it should pull the new version of the file. You will find a line:
2011092703      ; serial
in all of the files. This one was last edited the 27th of September 2011 and is the third revision for that day.

How to push the changes to Dns2

Make sure that the serial# has been changed in any edited files. Then run rndc reload on Dns1. This process happens every 15 minutes regardless.

Testing

To check that your changes worked properly use the nslookup command. Lets say that you wanted to check game.cslabs. You would run:

root@dns1 ~]# nslookup game.cslabs 128.153.145.3
Server:		128.153.145.3
Address:	128.153.145.3#53

Name:	game.cslabs.clarkson.edu
Address: 128.153.145.36

root@dns1 ~]# nslookup game.cslabs 128.153.145.4
Server:		128.153.145.4
Address:	128.153.145.4#53

Name:	game.cslabs.clarkson.edu
Address: 128.153.145.36

This shows that both Dns1 and Dns2 resolve game.cslabs to 128.153.145.36 which is correct.