Spamhaus users (Internet networks and end users that use Spamhaus's blocklists) use our blocklists freely and voluntarily, specifically because they do not want incoming email from IP addresses that we advise do not fully comply with Spamhaus's policy for acceptance of inbound email.

It is also important to understand that your email never touches Spamhaus's network, nor is it being intercepted or re-routed by us. The mail server you are sending to (the one that is rejecting your messages) is using a filter, set up by the owner of that mail server, that checks to see if the IP address you are sending from is listed on a Spamhaus blocklist. If it is listed, depending on the policy of the mail server owner the mail server may accept, flag for further filtering, or reject your message. How Internet mail servers handle incoming messages is governed solely by the mail server owners, not Spamhaus, we can only state whether an IP address complies with our published policies or not.

A diagram to help you understand how our blocklist technology works, where mail is being filtered and by whom, is here: http://www.spamhaus.org/whitepapers/dnsbl_function.html

The U.S. CAN-SPAM Act does indeed not ban the sending of Unsolicited Bulk Email, it merely outlaws the sending of Unsolicited Bulk Email with false or misleading sender information (and other specified conditions).

The fact that sending Unsolicited Bulk Email is not illegal in any particular country in no way overrides Spamhaus SBL Policy, nor ISP spam filter policies. CAN-SPAM specifically permits networks and Service Providers, including Spamhaus, to filter (prohibit/reject/block) incoming spam per each network's own policies. Nor does it override ISP contracts, whose Terms & Conditions of Business all stipulate that sending Unsolicited Bulk Email is prohibited by contract.

If you wish to send bulk marketing communications to Spamhaus users, you must abide by Spamhaus SBL Policy.

The Spamhaus Block List ("SBL") Advisory is a database of IP addresses which do not meet Spamhaus's policy for acceptance of inbound email and therefore from which Spamhaus does not recommend the acceptance of electronic mail. SBL listings are based on Spamhaus' definition of "Spam" meaning "Unsolicited Bulk Email" ("UBE") (see The definition of "spam"). Spamhaus does not evaluate the content or legality of spam, merely whether a message is spam by our definition or not. The responsibility for complying with Spamhaus SBL policy and preventing UBE being sent to Spamhaus users begins and ends with the bulk email sender.

The fact that sending Unsolicited Bulk Email is not illegal in a certain country in no way overrides Spamhaus SBL Policy, nor ISP spam filter policies. Nor does it override ISP contracts, whose Terms & Conditions of Service all stipulate that sending Unsolicited Bulk Email is prohibited.

If you wish to send bulk marketing communications to Spamhaus users, you must abide by Spamhaus SBL Policy.

The Spamhaus Block List ("SBL") Advisory is a database of IP addresses which do not meet Spamhaus's policy for acceptance of inbound email and therefore from which Spamhaus does not recommend the acceptance of electronic mail. SBL listings are based on Spamhaus' definition of "Spam" meaning "Unsolicited Bulk Email" ("UBE") (see The definition of "spam"). Spamhaus does not evaluate the content or legality of spam, merely whether a message is spam by our definition or not. The responsibility for complying with Spamhaus SBL policy and preventing UBE being sent to Spamhaus users begins and ends with the bulk email sender.

Spammers should be advised that frivolous US-style SLAPP suits, filed in the hope of harassing one's opponent, are not possible in the UK.