Maintained by: NLnet Labs

EDNS RRs

W.C.A. Wijngaards
Fri Nov 20 10:11:32 CET 2015


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Hi Ian,

On 11/19/2015 09:47 PM, Ian Cohee via Unbound-users wrote:
> Hello all,
> 
> One of our engineers discovered some interesting behavior while
> testing bad EDNS RRs in Unbound. He discovered that Unbound
> properly checks and identifies a truncated OPT RR as a FORMERR, but
> then returns the truncated OPT RR, resulting in a malformed
> response to a malformed request. I have attached a PCAP file that
> should contain the malformed requests/responses.

There is a fix now, unbound will remove the EDNS section from that reply.

This may cause the sender to think the server does not support EDNS
and then drop EDNS from its queries - and that is exactly right
because its EDNS contents cannot be parsed.

Best regards, Wouter

> 
> Has anyone observed this behavior, and if so, had issues from it?
> 
> I'd also like to hear some opinions about this behavior.
> 
> Thanks,
> 

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