Mail to nowhere

[Steve Matzura]

On Tue, 16 Jun 2015 17:31:07 +0000, you wrote:

>By default, most MTAs only listen to localhost, so don't accept
>externally derived mail. Try telnetting to port 25 on the machine
>from some place off your machine's network. If you get a "hang",
>it's likely a firewall issue. If you get a "connection refused"
>message it's probably that the MTA isn't listening on the external
>interface.
>
>If the MTA responds, do a manual delivery exchange and see what you
>get.
>
>If you're not seeing anything in your maillog, this is very likely
>an issue with your MTA's configuration, not dovecot.

Now that I think about and concentrate on what you wrote, make perfect
sense. Add to that the fact that I received bounces from my ISP that
all said the same thing: Unable to establish an SMTP connection. The
return code was 4.5.1.