Maintained with the help of ISPs worldwide, the Spamhaus PBL is a DNSBL database of end-user IP address ranges which should not be delivering unauthenticated SMTP email to any Internet mail server except servers provided for specifically by an ISP for that customer's use.

If you are an ISP, having a secure PBL ISP account gives you full control of your network's PBL-listed IP space, allowing you to add, edit and delete IP ranges under your control as well as set specific policies for specific ranges (including allowing or dissalowing removals from certain ranges). Submitting your dynamic or non-MTA customer IP ranges to the PBL database takes just minutes, costs nothing, and has a number of immediate benefits:

• You prevent infected computers in your dialup/DSL/cable IP space from being able to broadcast spam 'direct-to-mx' to networks that use Spamhaus spam filtering (covers billions of mailboxes)
  
  
• Your network's image benefits from no longer being seen by hundreds of millions of internet users as a source of proxy spam for phishers, scammers, pornographers and drug dealers.
  
  
• You block outgoing spam without upsetting your customers. Any customers who insist on running mail servers in your dialup/DSL/broadband space listed on the PBL are able to remove their IPs from the PBL immediately and simply.
  
  
• Your Abuse desk has far less complaints of spam from your dynamic IP space to deal with.
  

Spamhaus encourages all dialup, DSL and cable modem providers to participate and submit their own PBL ranges. To participate, Sign up here for a PBL ISP account.