Is port 53 required for both incoming and outgoing

[Michael Breton]

> -----Original Message-----
> From: Eric Smith [mailto:es at fruitcom.com]
> Sent: Friday, November 07, 2003 7:38 AM
> To: comp-protocols-dns-bind at isc.org
> Subject: Is port 53 required for both incoming and outgoing
> 
> 
> Hi
> 
> We have a primary NS on a network which has port 53 open for
> outgoing traffic only tcp and udp - not incoming traffic.
> 
> Is it still possible to run bind on this machine which is the
> primary NS for a domain?

Yes, as long at the origin of the queries to this DNS server is not from the
other side of the firewall.

If there will be queries from the outside, then you need to allow al least
UDP 53 incoming as well.  If there will be zone transfers from outside, you
will need TCP 53 also.

Michael Breton
Commtel