What controles this 'spam(no null-header or sender address)'

[Carl Boberg]

> 
> A while ago we started getting mail marked as spam that where 
> from mailinglists automatic senders and others with empty 
> return-path : Return-Path: <g> or similar
> 
> They get flaged as spam with no spamscore and just this 
> statement in the Spamreport (Mailwatch):
> spam(no null-header or sender address)
> 
> How can i stop this behaviour?

Replying to my own post :)
I had missed the setting:
Treat Invalid Watermarks With No Sender as Spam = spam

Just changed it to 
Treat Invalid Watermarks With No Sender as Spam = nothing

The scary thing with this setting is that when set to other settings than "nothing" MS completely ignores all other spamchecks and just marks the email as Spam / High-spam

Whatever, all is well again :)

/ carl