DNS Ports?

[chmilz]

Hi All,

I was just wondering if DNS uses any ports other 53 to communicate with other DNS Servers?

Here is my problem. Our organization has two external DNS Servers. One is currently sitting behind our firewall and the other is currently sitting in the DMZ.

We would like these two DNS Servers to replicate DNS information back and forth with each other but for some reason they can't connect to each other. We have Port 53 Open on the firewall (TCP And UDP) and still nothing.


I am wondering if I am missing something... any help is greatly appreciated and if you need any more info I can provide it.

Thanks!

 

[GlenJohnson]

The replies are sent on UDP ports 1022 and up, and they will change with each response. The queries stay at UDP port 53, only the replies change.

Glen A. Johnson
"Give the laziest man the hardest job and he'll find the easiest way to do it."

Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884

 

[chelenegro]

Glen, I am currently setting up something similar to what chmilz describes. What you mention is for the DNS query/reply flow. But to allow zone xfers through the firewall ... should any specific TCP port be opened?
Thanks a lot!

Jose Luis Martin Cenjor, CCNA, CCNP
HP Global Technology Solutions

http://www.hp.com

 

[ChrisAC]

To allow zone transfers from your firewall to an outside DNS server you will need to allow TCP53. If you allow UDP and TCP 53 to your firewall then everything should work.

If this does not work then your problem is most likley down to the DNS configuration, not the firewall.

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[GlenJohnson]

Try opening the other ports and testing it. If iproute is correct, then the problem will not be solved. I don't know what you're using for a firewall , so I can't really say. I can't find anything else. Good luck.

Glen A. Johnson
If you're from Northern Illinois/Southern Wisconsin check out Tek-Tips in Chicago, Illinois Forum.

Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884