[76987] in North American Network Operators' Group
Re: Port 25 filters - how many here deploy them bidirectionally?
daemon@ATHENA.MIT.EDU (Suresh Ramasubramanian)
Sun Jan 9 20:53:30 2005
Date: Mon, 10 Jan 2005 07:23:01 +0530
From: Suresh Ramasubramanian <ops.lists@gmail.com>
Reply-To: Suresh Ramasubramanian <ops.lists@gmail.com>
To: Sean Donelan <sean@donelan.com>
Cc: nanog@nanog.org
In-Reply-To: <Pine.GSO.4.58.0501091450510.13484@clifden.donelan.com>
Errors-To: owner-nanog-outgoing@merit.edu
On Sun, 9 Jan 2005 14:51:31 -0500 (EST), Sean Donelan <sean@donelan.com> wrote:
> On Sun, 9 Jan 2005, Suresh Ramasubramanian wrote:
> > 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?
>
> Have you looked at the following :-)
>
> http://www.outblaze.com/main.php?id=antispam&page=anti_infoadmin
I wrote some part of that doc (though the part about filtering you
quoted seems to have been written by a colleague) - you'll find docs
all over the 'net, that have a lot more detail.
Finding out how many ISPs are doing this is a rather different thing
from finding out how many docs out there are recommending it.
Especially as I'm seeing a marked uptick in this sort of behavior,
from ISPs that I thought normally do filter port 25.
As John points out earlier there were cases of specific people doing
this, though now I think we're seeing trojans do it - a rather more
dangerous development.
--srs
--
Suresh Ramasubramanian (ops.lists@gmail.com)
