Re: [Exim] silently dropping connections on high bandwidth l…

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Autore: Andreas M. Kirchwitz
Data:  
To: exim-users
Oggetto: Re: [Exim] silently dropping connections on high bandwidth load
Philip Hazel <ph10@???> wrote:

>> If Exim drops the connection, it usually happens within the first
>> about 5 seconds after the connection has been initiated from the
>> outside world (Internet).
>
> I think the first thing to try to find out is whether it is Exim, or
> your OS, that is dropping the connection (3-way TCP handshake not
> completing in time?). But I don't know how to do this. Maybe tcpdump
> could help.


Yes, you're right... after I wrote my mail to the list, I continued
debugging my problem, and I could reproduce that effect with other
daemons (like INN) as well. I'm very sorry that I suspected Exim to
have a problem (I use Exim for years and it's one of the most stable
software I've ever used).

Now it's obvious that it's the operating system that drops the
connections. The default timeouts for the initial setup of a
TCP connection seem to be quite low on Linux if one wants to
run Internet services over a heavily used ISDN line. ;-)
I haven't found out yet what kernel parameters need to be changed,
but I'm confident that I'll find the answer eventually.

Sorry to have bothered you and all the list members with my
problem which is clearly not Exim's fault.

    Greetings and thanks for your patience ... Andreas