New as of November 2009: A public version of the filter is available in industry-standard dnsbl format. Details..
Setup is easy: Create an account. Configure your filtering preferences, specifying which hosts quorum should accept queries from. Issue some test queries if you like. Finally, configure your receiving software - either by using a plug-in or by using the software's built-in dnsbl support (ask how). Educate your users about how they can contribute to the filtering database by using the quorum link in their email headers. Or go even further and implement a "report spam" feature within your user's mail environment.
Once you set it up, your mailserver will consult quorum for every message sender. When senders have not been seen before, your mailserver will ask the sender to try again later. In the mean-time, quorum will decide whether to allow or reject mail from the new sender.
When a message is rejected, your mail software will provide a web address in the bounce. The sender may use this link to ask that their mail be allowed in the future.
When a message is accepted, your mail software will insert a web address in the headers of the message. The recipient of the message may use this link to ask that mail be rejected in the future.
Click for a large, PDF version (27K)
Your mail software will not handle new senders properly or add links to received message headers without a plug-in.
There is already a postfix plug-in you can download here. Other mail software is currently not supported but we look forward to working with our clients to develop good solutions for all systems. We are particularly interested in adding qmail and sendmail support.
There is a public dns interface as well as a lookup form on this website.
