port 53 tcp/udp
borg at borg1911.com
Tue Jul 17 22:07:05 UTC 2012
* Mark Andrews <marka at isc.org> [2012-07-18 07:43:34 +1000]:
> In message <20120717194840.GA3773 at glasya2>, nex6 writes:
> > when does bind or dns in general use tcp and when does it use udp?
> When it needs to. TCP support is NOT optional.
> > from what i have read, from the client intial request if under 512b
> > come in on UDP port 53, if and depending on the local
> > resolver in needs to retry it *could* be a tcp port 53 request?
> > now thats client to name server;
> > what about, recursive lookups? or forwarded requests? etc
> It's still client to server. Recursive servers have a client side
> and a server side.
> > how does that work?
> Exactly the same why.
> > -Nex6
Thanks for the reply, i have an internal client with there own NS that is blocking TCP port 53, and complaining of random
issues. like our NS not sending them traffic randomly.....
I told them to unblock port 53 tcp.... then call me....
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> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742 INTERNET: marka at isc.org
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