Dear David Lord -

> I've still not worked out if you want mail coming in via postini to be
allowed
> to be relayed or if postini is just an external filter for scanning some
of your
> incoming mail. If the latter, I can't see why it should need to be treated
different
> to any other incoming email. However you've mentioned putting an entry for
> postini in smtprelay.tab which would indicate that you intend it is
allowed to
> be relayed. I can't see how that can be done securely though without
authentication.

Please understand that I support eMail for about over 300 Domains and
about 450 eMailboxes so changing ports would be large task. Further, you
are correct that the eMail from Postini plus outbound eMail from clients are
Relay'd on Port 25.

The problem is 1) the SPAMers are ignoring the MX records and
using a private look-aside IP Address Database(s) which allows the
SPAMers to bypass Postini by directly making a connection to the
xMail Server on it's IP Address on Port 25;

and 2) the SPAMers are constantly scanning IPs around the world
for new or moved eMail servers; therfore they will eventually any
"hidden" open Server within weeks -- I'm not just talking about an
Issuse with SMTP -- this includes ALL of  the protocols including the
more common FTP, SQL, SMB, etc.

Thefore, one has no choice but to lock the relay function to only accept
eMails from the upstream relay MTA; in this case Postini IPs. This is
easily doable on Many of the MTAs that I've come across in the past like
Microsoft Exchange; and RFC 4409 already proposed this concept.

Thanks,
Hal Dell
Managing Partner
ePodWorks.net, Inc.

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