Re: [Exim] connection refused on alcatel.co.uk

----- Original Message -----
From: "Daniel Zuidema" <daniel@???>
To: <exim-users@???>
Sent: Monday, July 22, 2002 11:53 AM
Subject: [Exim] connection refused on alcatel.co.uk


> I have a connection refused on mail.alcatel.co.uk but when I telnet to the
> server I get a line from sendmail so the server is up.
>
> Now I do have a bit of a weird setup, so it might be normal to refuse it.
>
> First of all, I've given the server a different name with dyndns. So my IP
has
> two names. The normal name from the provider and my dyndns-name.
>
> Second, I use fetchmail to collect mail from a different server and
maildrop to
> mine. For that domain I've build an alias-list. The e-mail address the
sender
> used isn't in the alias-list and so it's bounced. Very normal indeed,
because
> it isn't intended for anybody on the domain I fetched from, so the sender
used
> the wrong domain. (on the domain I fetch from are only 6 users, I know
them all
> personaly...)
>
> Now Exim is sending a bounce-message to the original sender. And the
mailserver
> of the sender is refusing the connection.
>
> Why? can it because it's a bounce-message? can it be that the mailserver
can't
> figure out the dns-name? or can it be something else?
>
> Daniel
>

Daniel,

Sounds very strange. If you are getting a genuine "connection refused" at
the
TCP layer, ie. an ICMP back from their system when you try and connect
but don't when you telnet then:

a) how could they have known that you message was a bounce *before*
you even tried to send it

b) could they be running some special sort of 'tcp wrappers' functionality -
maybe in a firewall? possible...

c) did you telnet to them from the same machine as your outgoing exim
delivery that fails? I had a problem on a Linux box with TCP Explicit
Congestion Notification (ECN) enabled that was being refused by certain
Sun boxes that had the Sun TCP Strong IP security installed/enabled
(can't remember the exact details)


Think that you should use TCP Dump or similar to see what's really
going on.


Mike