[76977] in North American Network Operators' Group
Re: Port 25 filters - how many here deploy them bidirectionally?
daemon@ATHENA.MIT.EDU (Christopher L. Morrow)
Sun Jan 9 11:26:36 2005
Date: Sun, 09 Jan 2005 16:25:43 +0000 (GMT)
From: "Christopher L. Morrow" <christopher.morrow@mci.com>
In-reply-to: <bb0e440a0501090625648426df@mail.gmail.com>
To: Suresh Ramasubramanian <ops.lists@gmail.com>
Cc: nanog@nanog.org
Errors-To: owner-nanog-outgoing@merit.edu
On Sun, 9 Jan 2005, Suresh Ramasubramanian wrote:
>
> .. and if it has been tried, have you noticed any issues with this?
>
> Please consider the situation of net abuse with the source address
> being an infected PCs on a dialup pool that has port 25 filtering
> enabled.
...description of 'fantasy mail' removed...
>
> So, a quick poll .. how many ISPs here have noticed this behavior, and
> applied bidirectional filters? And if they've applied port 25 filters
> bidirectionally, have they noticed any problems with this setup?
>
I believe reseller contracts have included this for over 2 years now, John
StClair's efforts to get these in place are the primary reason they exist
for our customers.
> This ISP's post is only the second I've seen noting such behavior in a
> few months, the first being a nanog post in Aug 2004 by Hank
> Nussbacher - http://www.cctec.com/maillists/nanog/current/msg03171.html
>
We'd first seen this behaviour over 2 years ago... quite a bit actually
over that time as the filters had been put into place.
-Chris
