[Mimedefang] OT: New Sendmail spam block

[Richard Laager]

On Thu, 2005-03-24 at 16:46 -0500, James Ebright wrote:
> The only issue with that is all if the broken/misconfigured MTAs out there....
> M$ exchange servers OFTEN send:
> 
> EXCHANGE.servernetbiosname.local as their HELO

That's acceptable damage. We have manual whitelisting and automatic
whitelisting in place to mitigate this. Also, under the example you've
provided, I'd only be adding SpamAssassin points, not blocking outright.
This helps limit the problem, especially since users set their own spam
filtering level.

I've only heard of a couple cases where messages are eventually being
rejected by SpamAssassin because of the 5 points I add for failing this
test. After contacting the administrators, this usually gets fixed
immediately.

> MS outlook express PCs often send their NETBIOS names as the HELO

I don't perform these checks for local machines or clients who have SMTP
authenticated. MUAs do a lot of stupid things, so I have a lot of
exceptions for local users.

-- 
Richard Laager <rlaager at wiktel.com>
Wikstrom Telecom Internet