A bug with Cisco’s SpamCop anti-spam service resulted in thousands of emails being blocked after being mistakenly marked as spam. The problem arose after SpamCop allowed its domain to expire, resulting in mail servers using the service to automatically reject outbound messages.
As a result of the domain’s expiration, thousands of organizations and email administrators around the world discovered that their outgoing emails were listed as spam and blacklisted on bl.spamcop.net. Administrators also encountered the following unhelpful message while checking their mail server logs: “The error on www.spamcop.net is: An error occurred while processing your request.”
After the SpamCop domain expired, visiting spamcop.net led to a redirection to the IP address of a domain parking service. This meant that every time SpamCop looked for a valid DNS record to see if an IP address had been associated with spam in the past, it would return a positive result.
