Re: blocking port 25 at the border?

[Mark Borrie <mark.borrie () OTAGO AC NZ>]

We have managed port 25 at the border for about 8 years. Only central
mailhubs are visible from outside. No local systems can send out on 25.

All mail domains are centrally registered and MXed to the incoming hubs,
which then route mail onto the mail servers.  Registered services smart
relay outgoing mail to the outwards hub service. Local clients must use
an on campus smtp host.

We initially set this up to stop open relays and other problems with
unpatched sendmail servers. Now virus and spam management are the prime
drivers. Interestingly, we are not seeing any impact from the Storm
worm. Our spam system must be catching the majority of the incoming and
we are not seeing locally infected systems (they could be there but they
cant send out and are probably trying to send directly anyway).

Mark

Bob Bayn wrote:
> Do you regulate port 25 at the border?
> If so, what is your procedure for allowing an exception
> (for a legit email server)?
> What administrative approvals were required at your
> institution before you could regulate port 25?
>
> Bob Bayn
> IT Security Team
> Utah State University
> Logan, UT

--
Mark Borrie
Information Security Manager,
Information Technology Services, University of Otago,
Dunedin, N.Z.
Ph +64 3 479-8395, Fax +64 3 479-5080, Mobile +64 27 609-6409