Re: [exim] Exim 4.69 SMTP timeout issue - 'unexpected discon…

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Szerző: Renaud Allard
Dátum:  
Címzett: Ted Dively
CC: exim-users
Tárgy: Re: [exim] Exim 4.69 SMTP timeout issue - 'unexpected disconnection while reading SMTP command'
Hello,

On Mon, November 17, 2008 23:09, Ted Dively wrote:
> Hi all.
>
>
> I've searched the docs and the rest of the Internet for some insights
> into this issue, but so far no answers have come to light. A sender from
> wamu.net is being bounced by my system, which is very annoying to the
> folks eagerly wanting to correspond with him. Here's the error message I
> see in exim_main.log:
>
> 2008-11-17 10:18:44 unexpected disconnection while reading SMTP
> command from mtav141.wamu.net (wamu.net) [167.88.162.70] (error: Operation
> timed out)
>
> The people hosted on my box can send email to this guy, but we can't
> seem to receive his replies.
>
> My research shows that others who've experienced the problem set
> smtp_receive_timeout from five minutes to ten. I didn't have that line in
> my Exim configuration file at all, so on the off chance it might help, I
> added it just above the message_size_limit line, like this:
> smtp_receive_timeout = 10m. I also commented out the rfc1413 lines, and
> just for thoroughness, I commented out the reverse DNS lookup warning, all
> to no avail.
>
> The box trying to send to us, mtav141.wamu.net [167.88.162.70] doesn't
> have proper rDNS, but it's important that we receive mail from these
> people, despite their poorly-configured mail server(s).
>


To my experience, this kind of behavior is almost always caused by a bogus
firewall at the other side which blocks communications when accessing an
"unauthorized port". That mean when checking ident, the firewall blocks
you and flush the rules. The thing here is that they seem to use different
mail servers for inbound and outboud mails, so this is not easily testable
remotely.
Try to avoid rfc1413 for this host (commenting it will make exim do the
tests with default timeout of 30s).