[100282] in North American Network Operators' Group
Misguided SPAM Filtering techniques
daemon@ATHENA.MIT.EDU (Owen DeLong)
Sun Oct 21 00:54:58 2007
To: nanog list <nanog@nanog.org>
From: Owen DeLong <owen@delong.com>
Date: Sat, 20 Oct 2007 13:12:14 -0700
Errors-To: owner-nanog@merit.edu
I'm seeing an increasing variety of misguided SPAM blocking
techniques such
that they are starting to become more and more annoying, and, I'm
curious as
to what solutions/work-arounds others have deployed, and, if anyone
has any
ideas on how to get these tactics reduced/stopped?
Here's the primary hinderance.
I use an authenticated TLS-protected mailhost at home for submitting my
email for delivery. Unfortunately, networks have taken to:
outright blocking 25 and 587 except to their own servers.
proxying all 25/587 connections in a manner incompatible with TLS
proxying all 25/587 connections in a manner incompatible with SMTPAUTH
blocking TLS startup on 25/587 connections
Primarily, I have run up against this in the following networks:
SPRINT Cellular network (can no longer send email from my phone)
Public wireless networks
Hotel networks
Other WiFi hotspots
Some DSL providers networks
I can't imagine that these tactics actually do anything to
significantly reduce
the amount of spam delivered to the internet, so, I'm curious as to:
1. Why are they used?
2. How do we convince operators to abandon them?
3. How prevalent is this problem, and, is it growing as I perceive?
Owen
