Re: [Exim] Ignoring bounce messages to alias - How?

On Fri, 6 Feb 2004, Nigel Metheringham wrote:

> People sending mail out through other routes (ie not via your server(s)
> but legitimately using your domain as a sender domain - ie people with
> laptops at home sending out via their ISP.

We treat mail that purports to come from our own domain but was in
fact launched from elsewhere as semi-bogus, deserving to be
intercepted for postmaster inspection.

Instead we encourage our users to configure their mail clients to use
secure authenticated SMTP via our mailer, using TLS, if they want to
use their departmental mail address as sender.

However, this isn't entirely without its problems, since some ISPs are
known to transparently divert their attempts to contact our MTA's port
25, to the ISPs own MTA.