[Mimedefang] OS wars... [was Viruses: Bounce or Discard?]

[Kevin A. McGrail]

> Better yet, use port 587 -- the generally recognized submission port

Sure, we just decided on 2025 like 4 years ago or more prior to the
submission queue standard.  Though I would bet ISPs will block 587 too.
ISPs around here are even blocking 110, 143, etc.  It's getting ridiculous.
The more non-standard your choice, the better and especially choosing a
non-standard, "unprivileged" port has it's benefits.  One of the
non-standard "standards" I've seen creeping up is 2525. ;-)

> - -- and protect it with the requirements that you must authenticate
> before submitting anything and (preferably) you must use TLS.  You can
> get away with running an extremely tight ship on an alternate port
> like 587, because you're not expecting random MTAs to contact you and
> attempt to deliver mail there, you're only expecting registered users
> to do so.

I am assuming they have anti-relay techniques whatever they might be.  We
use SSL and POP/IMAP auth before SMTP.

Regards,
KAM