[dns-operations] specifics of UDP response with truncate bit; odd google fail on AAAA responses w/ truncation

paul vixie paul at redbarn.org
Fri May 25 03:08:14 UTC 2012

On 5/25/2012 1:38 AM, Ryan Rawdon wrote:
> ...  So here are the questions I am left with right now:
> - Should a packet with the truncate bit set contain answers, or is this optional?  I'm guessing optional, but could see arguments for the UDP response with the truncate bit containing at least the first few RRs

the answers are optional.

> - Should a packet with the truncate bit set have the field for the number of Answers reflect how many answers are in that packet, or how many are in the actual forthcoming response?  I believe that it should contain the number of RRs contained in the UDP response itself, not the full answer to the query - and this is where I believe the Amazon response is malformed.  In the UDP response it says there are 24 answer RRs when there are zero

the header counts must match the actual contents but the
prospective/desired contents, or else the response is malformed.


"I suspect I'm not known as a font of optimism." (VJS, 2012)

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