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Re: ares "feature": Ignores responses from unexpected sources

From: Daniel Stenberg <daniel_at_haxx.se>
Date: Thu, 16 Oct 2003 17:15:07 +0200 (CEST)

On Wed, 8 Oct 2003, Henrik Storner wrote:

> I have a DNS server that accepts queries on one IP-address, but sends the
> answers with a different source-IP. A network trace says (IP's and
> domain-names changed):
>
> 10.29.31.155 -> 10.29.37.21 DNS C dns01a.foo.com. Internet Addr ?
> 10.29.10.5 -> 10.29.31.155 DNS R dns01a.foo.com. Internet Addr 10.29.37.21
>
> Note that the request is sent to 10.29.37.21, but the answer
> originates from 10.29.10.5.
>
> The "standard" DNS lookup tools and libraries (nslookup, dig, libresolv)
> happily accept this and completes the name lookup. Ares doesn't - it appears
> to just hang waiting for a response (it doesn't even timeout, from what I
> can see).

I would say this is a bug. At least it should timeout,

If you're still able to repeat this "effect", can you dig into
ares_process.c:process_answer() and see what it does to discard to response
and possible how it can be patched?

-- 
 Daniel Stenberg -- curl: been grokking URLs since 1998
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Received on 2003-10-16