# How to install 3rd DNS Server



## rj3k (Apr 4, 2011)

We do have primary & backup DNS. I'm planning to move the DNS02 to the new server(DNS03)& remove the DNS02 later. Ho can I do move all the information & configuration of DNS02 to the new server? Can someone help me on these steps configuring the DNS03 & removing DNS02. 

Thank you.


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## gkontos (Apr 4, 2011)

rj3k said:
			
		

> We do have primary & backup DNS. I'm planning to move the DNS02 to the new server(DNS03)& remove the DNS02 later. Ho can I do move all the information & configuration of DNS02 to the new server? Can someone help me on these steps configuring the DNS03 & removing DNS02.
> 
> Thank you.


Hi, I think this is a dns related question, irrelevant from upgrading or installing FreeBSD. In any case, assuming you are using bind, you don't have to touch anything on dns2. You should just declare dns3 as a slave of dns1 and let bind do all the transfer automatically for you. Have a look in the handbook for more information.


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## mamalos (Apr 5, 2011)

Another trick we use when we move *A, CNAME, SOA* or *PTR* records is to change the *TTL* of the entry of interest to 1. This way, when the default *TTL* expires, and hence all cached information becomes stale, the DNS servers around the world will require a new, "fresh" answer. This time the answer will have a *TTL* of 1 (on second), which means that the specific entry (or whole zone file if you like) will not be practically cached anywhere. Hence, once you change an entry, it will be available immediately to anyone, so there will be zero delay/"downtime". This can be achieved also with the zone regarding the *SOA* records you wish to change. This way, nobody will cache your "old" DNS servers after the *TTL* of your zone file has expired, and each change will become public immediately.

Good luck.


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## rj3k (Apr 5, 2011)

Thank you guys I will try all of your suggestions & will let you know after.


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