Re: Unable to connect to SMTP over internet

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From: Mark Arnold [MVP] (mark_at_mvps.org)
Date: 07/16/04 

Date: Fri, 16 Jul 2004 14:56:58 +0100

"Allen" <anonymous@discussions.microsoft.com> wrote:

>Hi.
>
>I have a strange problem that I hope someone here might
>have experienced or knows how to fix.
>
>I have an E2K on a W2K (both SP3) running behind a
>firewall. both ports 25 and 110 are open and have a rule
>to forward request via these ports to my Exchange server.
>POP3 clients are able to connect from the internet and get
>their emails. other mail servers across the internet are
>also able to connect to it for mail distribution (which I
>assume means that communication over port 25 is working).
>However, when a client is trying to connect the SMTP for
>send email via my mail server thet get the message that
>the mail server cannot be contacted on port 25.
>
>I did close my mail server for open relaying, but enabled
>the option to always allow sending messages with
>authentication. it works without a problem internally, and
>users from within my network are able to send emails using
>my exchange server when they set their mail program to
>send a user name and password in order to send an email,
>but it just not working from outside the internet.
>
>Thanks,
>
>Allen

If servers on the Internet can reach you to send you mail then end to
end is working ok. If the PC clients using POP can't send mail and get
a "cannot connect" error then I'd be looking at name resolution issues
as my first port of call.
Can they ping the name, what IP address do they get back, is it the
right address, do you see the traffic coming in when you monitor the
firewall? All that kind of thing.

Mark Arnold MCSA MCSE+M MVP, mark@mvps.org
FAQ: http://www.swinc.com/resource/exchange.htm &
http:http://www.swinc.com/resource/e2kfaq.htm

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