[55538] in North American Network Operators' Group
Re: Remote email access
daemon@ATHENA.MIT.EDU (Mike Tancsa)
Thu Jan 30 21:06:44 2003
Date: Thu, 30 Jan 2003 21:03:23 -0500
To: Dave Crocker <dhc2@dcrocker.net>
From: Mike Tancsa <mike@sentex.net>
Cc: nanog@trapdoor.merit.edu
In-Reply-To: <106555489101.20030130174637@brandenburg.com>
Errors-To: owner-nanog-outgoing@merit.edu
At 05:46 PM 1/30/2003 -0800, Dave Crocker wrote:
>Blocking outbound SMTP (port 25) is supported by the Ops community as a
>spam-suppression mechanism. Ops support for this blockage appears to be
>deeply and broadly held.
A large chunk of the spam I am seeing these days are due to exploitable
formmail.pl scripts (i.e. insecure customer web apps) and open proxies
(1080,8080 3128 etc). These forms of delivery are also preferred by
spammers as their original IP addresses are hidden. Blocking port 25 will
do nothing to stop this.
I would be surprised if your premise holds true, that the majority of the
Ops community support this. Blocking port 25 results in lost customers as
well as additional support headaches. I know when the local big ISP
(Sympatico) starting blocking port 25, we gained quite a few business
customers. So our sales staff certainly supported their Ops implementing it.
---Mike
--------------------------------------------------------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike@sentex.net
Providing Internet since 1994 www.sentex.net
Cambridge, Ontario Canada www.sentex.net/mike
