DNS problems to RoadRunner - tcp vs udp

John Kristoff jtk at ultradns.net
Fri Jun 13 19:05:44 UTC 2008

On Fri, 13 Jun 2008 14:14:55 -0400
Jon Kibler <Jon.Kibler at aset.com> wrote:

> TCP is used for zone transfers.
> If my server responded to TCP queries from anyone other than a secondary
> server, I would be VERY concerned.

I wouldn't be unless it looked like a DDoS - and it might for some that
are seeing the results of a DNS-based DDoS mitigation device you or an
upstream put in for the first time.  These boxes force clients to switch
over from UDP to TCP for queries when a well formed UDP DNS attack hits.


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