Port 25 and Static/Dynamic IP for Listserve SW

[Sandy Harris]

Just to clarify for anyone not up on the terms here.

An MTA (mail transfer agent) handles server-to-server
mail transfer, SMTP protocol on port 25. Sendmail,
qmail and postfix are examples.

Client programs -- such as Berkeley Mail, Pine, Mutt,
Thunderbird or the client in Evolution -- deal with the
user and hand off mail to an MTA for delivery. This
can be done on your machine if there's an MTA
running locally, or they can transfer to a remote
MTA using a protocol such as POP or IMAP.

Mailing list managers -- such as Majordomo or
Mailman -- run mailing lists. They also depend
on an MTA for their input and output. I think in
this case it has to be a local MTA, but I could
be wrong.

Every ISP runs an MTA for its customers. Most
customers will get mail from that with POP or
IMAP and hand their outgoing mail to it for
delivery.

The ISP may also (possibly for an extra fee)
let customers run their own MTAs which are
set up to relay everything through the ISP's
MTA. The term "smarthost" is used; I'm hazy
one exactly what it means.

The simplest solution for you is to go to a
company that specialises in hosting, and
pay them to register some domain such
as "pumpkineater.com" and run a server
for it with mailman plus some MTA and a
web server. That gives you everything you
need, including an automated web archive
of the mailing list(s).

An alternative is to talk to your ISP. They
may do hosting and be able to provide
those services. Or they may support a
smarthost solution where you run both
a mailing list manager and an MTA on
your server.

Just trying to run your own MTA without
smarthosting (that is, without piping
everything through the ISP MTA) is
likely to cause problems. Spammers
do that, firing off messages to mail
servers from dynamic IP addresses.
It is therefore common both for ISPs
to block outgoing connections to Port
25 and for recipient servers to refuse
messages from dynamic IP addresses.

-- 
Sandy Harris,
Quanzhou, Fujian, China