Thanks for your reply, Eugene.
The full message returned by Exim is :
503 Command refused, required Proxy negotiation failed
As specified in :
/usr/share/doc/exim-4.84/doc/experimental-spec.txt
It is mainly due to non-respect of the 3 seconds timeout, because of high
traffic, for instance. Exim is waiting 3s max, that haproxy sends to it
the PROXY instruction.
I understand that the real problem to solve is the high traffic, but
replying by a 503, which will generate to the end user a mail with "503 -
REJECT - FORGET ME", is quite hard to explain to the users. So, it is why
I thought about a 4xx error.
Sylvain
Le 21/07/2015 11:46, « Evgeniy Berdnikov » <bd4@???> a écrit :
>On Tue, Jul 21, 2015 at 10:53:36AM +0200, Sylvain Donnet wrote:
>>
>> I have two servers, one with Haproxy and its send-proxy experimental
>> feature, and a Baruwa server, with exim installed on it. Sometimes,
>> I got bunches of proxy 503 errors, due probably to overloads in
>> traffic. They are very annoying for my customers.
>
> Does Haproxy replies with SMTP status code 503 on overload?
> If so, this proxy should be fixed, not Exim.
>
> First, code 503 have meaming "Service unavailable" for HTTP,
> but for SMTP code 503 is "Bad sequence of commands" and this
> is completely unrelated with proxy overloads.
>
> I think that correct behaviour of proxy in case of overload is simply
> do not accept() new connections, then Exim as client could get timeout
> on connect() and keep mail in queue, retrying later.
>
>> Is it possible to change the 503 into a 45x error, just to tell to
>> the others SMTP MTAs to retry later (I cannot compile/recompile
>> exim, it is distributed by Baruwa) ? Or any other solutions to avoid
>> a returning mail to senders ?
>
> Wrong approach, IMHO.
>--
> Eugene Berdnikov
>
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