Port direction for zone transfer (not AD integrated)

ferrarista used Ask the Experts™
Hi guys,

I need  to forward a zone from DNS Server 1 to DNS Server 2 located in different network segments.

Can you help me to clarify what port it requires (I believe TCP 53) and what direction ? Is it the destination server (DNS Server 2) contacting the DNS Server 1 or the other way round ? or is it bi-directional ?

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Distinguished Expert 2018
You want TCP and UDP 53 when possible and you want it bidirectional as well technically a secondary DNS server should contact the primary at intervals so you onky NEED one way. But if you want changes to propagate faster, DNS Notify to the secondary gp the other way and tell the secondary DNS server to check in sooner.


Hi Cliff.

so it would suffice to open only one way from the forwarded server up to the forwarding server, right ? I'm not talking about UDP port, as naming resolution is then done by the receiving server, which is in the same network as its DNS clients.

You will want a bidirectional rule on UDP/53 and TCP/53 for pull and notify requests if you are using notify, which you should if you want updates propagating in a timely fashion. Do you have some security concern about a point to point firewall rule being a risk?
Seth SimmonsSr. Systems Administrator

No comment has been added to this question in more than 21 days, so it is now classified as abandoned.

I have recommended this question be closed as follows:

Accept: Cliff Galiher (https:#a42384867)

If you feel this question should be closed differently, post an objection and the moderators will review all objections and close it as they feel fit. If no one objects, this question will be closed automatically the way described above.

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