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Re: blocking port 25 at the border?
From: Gary Flynn <flynngn () JMU EDU>
Date: Thu, 23 Aug 2007 18:03:30 -0400


We're set up much like Mark described below and have been for a
similar amount of time.

There is no set policy or procedure for exceptions but there
has been only one request for the past several years so it
hasn't been an issue.

I can't recall what we went through to implement the change. We did
not have very many independent email servers at the time so that
helped a lot. We grandfathered the ones we could identify through
the policy change and they've slowly come into the fold over time.
The change may also have coincided with the introduction of a new
mail system which might have helped client migration.

P.S. Regarding the Storm worm SPAM follow up question I introduced.
I apologize for changing the subject of the thread without actually
changing  the subject line. I try not to do that.

Mark Borrie wrote:
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).


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

Gary Flynn
Security Engineer
James Madison University

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