Are you having email problems this morning? If you are getting bounce backs referencing SORBS, read on my friend. It appears that the Real Time Blacklist (RBL) SORBS made a critical error yesterday that is causing almost all email users havoc. (Internet Storm Center) Sometime yesterday, the SORBS anti-spam blacklist (their site is currently suffering from it’s popularity today) accidentally updated their databases to include an enormous number of the Internet’s mail servers and networks. This appears to have included IP addresses owned by Amazon, Google, Rackspace, and others were included in this blacklist and marked as unacceptable for email. (uTest)

If your mail server IP is listed within those IP ranges, then you more than likely won’t be able to send emails today to most anyone using the SORBS blacklist. On the flip side, if your mail server subscribes to the SORBS list, you may want to temporarily disable that setting until this issue is resolved.

RBLs like SORBS were originally created to help reduce the amount of email spam sent and received around the world. Typically a spammer will send their emails from one or two mail servers. If the spammers server can be located then the IP can be put into a “blacklist” of known spammers. Those blacklists are compiled and shared by independent groups, like SORBS.

Many ISPs, email providers and IT administrators will check these blacklists when they receive a piece of email. If that email came from a known spam server email will be rejected entirely. However, relying on any single source or RBL to block spam is not a best practice when the RBL is corrupted.

This can cause serious outcry, i.e. on Twitter.

For information about other Blacklists that have shut down or Blacklists that are having problems, view this forum post.