actually greylisting works pretty well, and the whitelist of exceptions is relatively small (not more than 300 entries as far as I remember). Also if you communicate the value of it to the customers, they tend to agree that having 90% of spam filtered before entering the system is worth waiting for half an hour for email from a new source.
It's also a matter of resources: if you don't want or cannot enable greylisting, you have to invest more resources into a more sophisticated mail filtering software. Even if it's available for free, still developing and maintaining your solution might become too expensive.
so, basically as we discussed it already last week in regards to Skype: use the right tools for the right task :-)
----- Original Message ----
From: Tonnerre Lombard tonnerre@bsdprojects.net To: swinog@swinog.ch Cc: swinog@lists.swinog.ch; per.jessen@enidan.ch Sent: Friday, October 17, 2008 5:27:10 PM Subject: Re: [swinog] RBL's (again) (Was: Anyone from Green here?)
Salut, Per,
On Fri, 17 Oct 2008 12:47:48 +0200, Per Jessen wrote:
Another option is to disable greylisting just for that one mailserver.
This implies that either you know all servers hosting broken scripts (NP-complete I think) or your customers will always communicate problems. Usually they encounter them and rant about it on their Stammtisch and then change provider to someone with one hell of a lot of SPAM.
Tonnerre