[Mimedefang] the right place to put greylist check?

[Kenneth Porter]

I wonder if it makes sense to tempfail at helo if you've never seen the 
relay before, and then do regular greylisting in a subsequent phase? On a 
busy server, that could cut a lot of load.

> Be aware of one more factor: Some buggy MTA's (Novell Groupwise for
> one, I believe, and ancient versions of SLMail from Seattle Labs) fail
> if all RCPT commands are tempfailed, and bounce (rather than queuing
> and retrying) the message.

Is Novell doing anything to fix that? How hard is it to identify these 
MTA's when they come knocking? Can they be spotted in Received lines?