Greylisting results

I introduced greylisting about a week ago on my mail server, with amazing results. ( see Nov 22nd )

Statistics of the mail server used to look like this:

now they look like this:

Most viruses stay outside now:

Those that make it through came through a real mail server, not a infected computer.

I wanted some statistics about the relation between accepted and rejected emails, so I created this:

As you can see 80% of all email traffic is blocked. This means that the server has much less load, it is less CPU intensive to check a greylist than to scan each and every incoming email for virus and spam.

Emails clearly known as Spam have always been rejected. As the spam detection had to have some security margin, me and my customers were still receiving some spam.

With greylisting, I had customers calling me on Monday saying that for the first time since they use email they had no unwanted mail in their inbox after the weekend!