e-Mail Hell

My e-mail has been mis-behaving again, and it took me a few days to straighten it out...

The only thing that wasn't working was sending mail - but just from Outlook on my home PC. Sending worked fine from Jeanie's PC, and from my notebook...

Strange eh?

Well, long story short, the problem turned out to be a combination of a bad setting in my sendmail.cf file and a configuration opportunity for my new firewall software and my old anti-virus software.

sendmail's sendmail.cf file defaults to having the following configuration line:

DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')

This configures sendmail to only listen on the loopback device 127.0.0.1 and not on any other network devices.

Of course, this prevents ANY other PC from connecting to the sendmail deamon.

I KNOW I had previously commented this line out - but somehow, it got set back to the default, so I commented it out again in sendmail.mc.

Once I had edited the sendmail.mc file, rebuilt the sendmail.cf file, and restated the sendmail deamon, I could at least connect to sendmail from another machine.

The way I was able to verify this was to telnet to sendmail on the host using the command

telnet address.of.host 25

Which opens a session on port 25 - the standard sendmail port.

Once I had gotten that far, I was able to then configure the firewall and anti-virus software to allow a connection from my home PC.

Now, you might be wondering why Jeanie's PC and my notebook worked with the settings above...

Well, Jeanie's PC is configured to send/receive direct from the ISP, and my notebook is configured to tunnel to my host via SSH - so as far as sendmail on the host was concerned, the connection was coming from itself!

Just for reference, the errors I was getting from Outlook were:

0x800CCC0E
0x800CCC0F
and
0x80040109

Once again, after much searching, and spending a fair amount of time on a few red herrings, Google did finally help guide me in the right direction.

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Posted by David at November 17, 2003 01:51 PM