Aw: Re: [OT] CLI for noobies: The keys to GnuPG

[Longman, Bill]

> In the situation I had in mind, the MTA running on your Mac connects
> directly to the MTA of your mom's ISP (or in any case to a mail
> exchanger for her domain), protecting your message on its way across
> the big bad internet.  If you route your outgoing mail through your
> own ISP's server, that counts as a relay and indeed all bets are off.
> Unfortunately it is becoming more and more necessary to do this if you
> don't have a static IP address, as many ISPs won't accept email
> originating from known dynamic IP ranges (as an anti-spam measure).

In addition, several other checks are used on some mail servers. The first
is that the SMTP client needs to have a DNS entry for itself. Some even
check to make sure that entry is an MX record.

If you follow this idea, your MUA would have to connect to all the MX
machines of all the people you email - a bit of a burden at the present
time.