RE: [OT] recomended DNS services?

["K. C. Li" <li@xxxxxxxxx>]

On Tue, 25 Apr 2006, Paul Gale wrote:

> How would having a backup mail service (incoming) open me up to more
> spam - are you talking about incoming or outgoing from me? It would
> all come through my server and would be picked up in the same way as
> it does now wouldn't it?

Normally, the secondary e-mail server would have been authenticated (or
the fact that it is an intermediate forwarding point) and thus bypass some
or all the UCE checks on the primary server. That is when spam would slip
through if the secondary is less stringent than the primary in terms of
UCE vetting.

Even if you treat the secondary server like any other incoming server
delivering e-mail, there are some effective UCE tests that could only
apply to directly connected incoming e-mail servers. For example, RBL
(Realtime spam Block Lists) checking would be useless because you would be
checking the secondary's IP address and not the real originating e-mail
server's. Other effective anti-UCE measures such as greylisting, reverse
DNS lookup, SPF, etc would also be rendered useless by the seconadry's
route.

Of course, if you currently don't do any of those UCE tests on your
primary e-mail server, you would have noticed no difference by adding the
secondary.

Regards,

Kwong Li
li@xxxxxxx
Laser Business Systems Ltd.
http://www.laser.com
http://www.cbus-shop.com