Guide on setting up Master & Secondary DNS Servers

[SiddeswaraK]

Hi,

I have two VPS with two different Datacenters. I am running my website on one of the VPS which has Plesk Panel 11.5 installed on it. Since my second server is not in use, I would like to use it as a Secondary DNS Server for redundancy. I know this can be done with Plesk Expand. But, I am not in a position to invest further as I just run 4 domains on my main server. I was looking at installing some free control panel on my secondary VPS and set it up as a Secondary DNS Server if possible. But, I could not find any Guides on setting this up.
Can anyone point me out to some guides or explain in brief how I can do this? I see that we have an option in Plesk - 'Switch DNS Service mode' which can be used to either setup my first server as a Secondary or Primary. I have installed Webmin/Virtualmin on the second server, but am confused as to how to set this up perfectly. Can anyone help me with this? I can reinstall the 2nd Server if required, but not my first one with Plesk.

Thanks in advance.

 

[Faris Raouf]

You don't need to make any significant changes in Plesk. Webmin on your other VPS will do fine. And with 4 domains (or 10 or 20) this will be absolutely fine.

1) In Webmin, Create new Slave zone. See http://doxfer.webmin.com/Webmin/BINDDNSServer for details.
(hint: zone type=forward, Records file - automatic, Master servers = IP of Plesk VPS)

2) Repeat item 1 for all four domains

3) In Plesk, Tools & Settings -> DNS Template Settings >> Transfer Restrictions Template, add IP of your webmin VPS to allowed list

4) Make your "ns2" point to IP of webmin VPS instead of Plesk (Remember to do this in the Registrar's nameserver host records as well as in the DNS records for your namesever domain. (i.e. if you have ns1 and ns2.maindomain.tld, then you need to change the A record for ns2 in the DNS for maindomain.tld AND you need to change the nameserver host record for ns2.maindomain.tld, which you will have originally created via your registrar's control panel and which you can only change in your registrar's control panel)

Now, if you add a new domain to Plesk, all you need to do is also add a new Slave zone record in webmin for that domain.

It would be helpful for you to know some things about the way DNS servers work in order to avoid confusion, however:

The Slave (aka secondary) DNS server needs certain information before it can act as a Slave. Specifically, it needs to know the name of the Zone (which is a domain name in this case) it will be acting as Secondary for, and also the IP address of the Master.

It needs this information because in ALL cases (as far as I'm aware), it is always the Slave that initiates the data transfer process where information (DNS records) is communicated from the Master to the Slave. In other words, it is always the Slave that asks the Master for the data. The Master does not just sent it to the Slave automatically.

The Slave asks the Master for this information when:
1) The Master tells the Slave that it has new DNS information.
2) The Master namserver is restarted
3) The Expire value in the SOA part of the Zone record is reached (at which point the Salve considers the information it has may be too old).

The Master knows the IP address of the Slave for a particular Zone from the NS records contained in it.
The Master will ignore any requests to transfer data from any IP that is not a list of allowed IPs. This is controlled in Plesk via the Transfer Restrictions Template

To debug:
On the Slave VPS:
# tail -f /var/log/messages (usually, anyway -- may be different for non-Centos)

On the Master (Plesk) VPS
# service named restart
# tail -f /var/log/messages

Then watch what happens in /var/log/messages on the Slave. You should not see any significant errors.
Check /var/log/messages on the Master (Plesk) server also for dns-related errors

 

[SiddeswaraK]

Wow... Thank you, Faris.. That just sounds like good reading for me. I'll check this out and update again on this thread on how it went. Thanks for taking time out to point me out to something I can work on. Really appreciate your help.

 

[SiddeswaraK]

Thanks, Faris.. I followed your instructions and everything seems to be working good. I could see the slave zone on the Secondary DNS Server populated with the records from the Primary. I'll play around with it some more seeing that now I have got some points to ponder over from you.. Thanks a lot!!

 

[Roland_R]

Thank you! Is it possible to sync the domains/records?