Here are 4 things that we recommend in order to stay off the UCEPROTECT-Blacklists and the Backscatterer List:

1. Do not use abusive techniques on your systems, and also tell your customers with their own servers not to do so.

The following techniques are considered abusive, even though some seem to have become very popular.
Sender callouts (also known as Sender Verify or SAV) or any other kind of Backscatter.

via UCEPROTECT®-Network – Germanys first Spam protection database.

2. Ensure that large amounts of garbage cannot be sent through your mailservers / smarthosts.

3. Ensure that your dynamic / dialups / homeusers cannot be abused as spam zombies.

4. Get clue about new customers, secure your servers and prevent open relays and open proxies at your dedicated line customers and at customers with static IP addresses.