[Dshield] ISP's blocking dynamic IP address mail servers

Micheal Patterson micheal at tsgincorporated.com
Wed Apr 21 20:24:53 GMT 2004

----- Original Message ----- 
From: "Laura Vance" <vancel at winfreeacademy.com>
To: "General DShield Discussion List" <list at lists.dshield.org>
Sent: Wednesday, April 21, 2004 10:44 AM
Subject: [Dshield] ISP's blocking dynamic IP address mail servers

> Hello,
> I'm not sure if this is the right list, but I believe it is a result of
> all of the attacks to port 25 that have been happening.

That and due to the problem of systems getting compromised and becoming
unwilling / unknowing spam / virus / trojan zombie's that bombard their
payload (viril or spam) to the rest of the worlds mail servers. It is
impossible to block them and maintain that block unless you block the
dynamic ip range that these systems are using. Cox Cable for one, and I've
seen mention that others may follow suit, are starting to even prevent their
clients from sending and receiving to port 25 off their network to curb this
problem forcing clients to use their specified mail servers for sending


Micheal Patterson
TSG Network Administration

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