[dns-operations] DNS deluge for x.p.ctrc.cc

Joe Greco jgreco at ns.sol.net
Mon Feb 27 16:50:09 UTC 2006

> On Mon, Feb 27, 2006 at 12:20:28AM +0000, Paul Vixie wrote:
> > # What other applications using larger packets would it break?
> > 
> > responses containing AAAA RR's are one example.  RFC 2671 was not written
> > pointlessly, or at least i hope (as its author) that it wasn't pointless.
> What about query size limit.  At least for servers, or any host for
> that matter, that would never receive DNS answers itself (e.g. in the
> case of an authoritative only server), would limiting packets to 512
> filter something potentially legitimate?
> I realize this doesn't particularly help most victims in the wave of
> attacks being discussed here, there have been attacks that shower 4KB
> answers at hosts that should never be getting those answers.
> Yes, I realize filtering at this granular level this is just a
> band-aid.  Just curious in understanding what limitations there might
> be on questions.

And, from the answer side of things, it is kind of too bad that there is
no way for a client to signal back "I didn't ask you that question", or
for a recursing nameserver to do something useful with a port unreach,

... JG
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

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