SORBS' Closing Has Been Announced

I've heard rumors for a few days that Proofpoint was closing the SORBS (Spam and Open Relay Blocking System) DNSBL. Still, I had not seen any real confirmation until last night, when the list maintainer sent an email to the Mailop mailing list. So, I now feel comfortable posting that SORBS is closing over the next few weeks.

Details about how the shutdown will happen are sparse. The SORBS website does not yet indicate that any changes are coming, other than the now years-long promise of "new manager tools" to help registered users "manage their IP netblocks." Hopefully, that will change in the next few days and give some clarity on the process and timeline.

SORBS has a long and somewhat checkered history. It was created in the early 2000s, with a DNSBL (Domain Name System-based Blocklist) version coming online in January 2002. It was sold to GFI in 2009.¹

During my early days at ExactTarget (now Salesforce Marketing Cloud), starting in July 2010, many of our IPs were listed on SORBS with an explicit notation that the listings would not be removed due to the list maintainer's personal issues with another employee. The intervention of another ET employee eventually broke that impasse, and the listings were removed several weeks later. I never considered that a sign of a fair or well-run list (and have remained pretty biased against its use since then). Steve Atkins at Word to the Wise published a blog series on SORBS in December 2010, highlighting various issues with the service.²

GFI sold the list to Proofpoint in July 2011. Since then, SORBS has remained at Proofpoint, operating as one of the many public DNSBL services that SMB and hobbyist email administrators sometimes use to block potential spam sources. The complaints have mostly died off over the last few years.

The closure does not change much for senders. SORBS was one of the oldest DNSBL services, but it mainly helped hobbyist email administrators filter spam. Its controversial history and management issues made it a source of frustration for many in the industry and depressed its overall use, and SORBS listings have not carried much weight in the email marketing space for many years.

Email administrators who still query SORBS will move to other DNSBL services, and there are many to choose from, some better maintained than others. They shouldn't wait for a transition announcement from Proofpoint to do it. A list that is being shut down is not one to trust with blocking decisions in the meantime.