Re: Port 25 blocking

[Charlie Prothero <Charlie.Prothero () KEYSTONE EDU>]

We're doing the same thing, for the same reasons.  Only one user even
noticed.  Apparently, his "home" ISP maintained a completely open relay,
which allowed him to send mail from our campus network.  Once we showed
him that he could still POP mail from his ISP, but use our SMTP server
to send, he was OK.

Charlie Prothero
IT Director
Keystone College

-----Original Message-----
From: Matthew Keller [mailto:kellermg () POTSDAM EDU] 
Sent: Friday, March 05, 2004 5:18 PM
To: SECURITY () LISTSERV EDUCAUSE EDU
Subject: Re: [SECURITY] Port 25 blocking

We are blocking outgoing and incoming port 25 traffic to everything but
our official mail servers. While this has created some minor waves, it
has been widely accepted. Our motivation was to prevent some of the spam
zombie viruses from using our systems to spam systems elsewhere on the
Internet. We try to be good netizens. :)

On Fri, 2004-03-05 at 14:10, Tim Boshart wrote:
> Our department has started to discuss blocking port 25 at our firewall
> for all machines except for our mail servers. How many places are
doing
> this? Why did you implement this?
> --
> Tim S. Boshart             Information Technology Services
> Goshen College             Voice: (574) 535-7004
> Email: timsb () goshen edu    http://timlinux.goshen.edu/
>
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--
Matthew Keller
signat-url: http://mattwork.potsdam.edu/signat-url/
"No one ever says, 'I can't read that ASCII E-mail you sent me.'"

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