Compression / Pointers on returned queries

Kevin Darcy kcd at
Thu Jun 5 03:10:55 UTC 2008

Brian Feeny wrote:
>> -----Original Message-----
>> From: Mark_Andrews at [mailto:Mark_Andrews at]
>> Sent: Wednesday, June 04, 2008 9:57 PM
>> To: Brian Feeny
>> Cc: bind-users at
>> 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.

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

More information about the bind-users mailing list