Compression / Pointers on returned queries

[Mark Andrews]

> Brian Feeny wrote:
> >   
> >> -----Original Message-----
> >> From: Mark_Andrews at isc.org [mailto:Mark_Andrews at isc.org]
> >> Sent: Wednesday, June 04, 2008 9:57 PM
> >> To: Brian Feeny
> >> Cc: bind-users at isc.org
> >> Subject: Re: Compression / Pointers on returned queries
> >>
> >>
> >> 	Why do you care?  As long as you get the answer in a single
> >> 	packet it makes little to no difference.  Also why are you
> >> 	asking recurive queries?  If you want to test authoritative
> >> 	servers then you should be making non-recursive queries.
> >> 	The server should also be configured not to accept recursive
> >> 	queries from anywhere.
> >>     
> >
> > Because a response of >512 bytes causes pain because of firewalls/etc that
> > may drop the packets by default.
> >   
> How old are these devices? RFC 2671 was published in August of 1999.

	RFC 1034 was published in 1987.  These boxes aren't even
	RFC 1034 compliant.
 
> Note that you can configure named use 512 as its EDNS0 buffer size, to 
> get around middlebox obsolescence/brokenness. See "edns-udp-size" in the 
> ARM documentation.
> 
> - Kevin

	Which only works if the server talks EDNS which it doesn't.

	Mark
-- 
Mark Andrews, ISC
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PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org