03/26/2008

I have received a number of customer calls in the past 24 hours where all inbound mail is being blocked as spam at the Domino server. Subsequent research into the issue showed that the DNS RBL (Real-time Black List) at relays.ordb.org is the cause.

The ORDB blacklist was created by Thomas Jensen in 2001, it ceased operation on December 18, 2006 and the website was retired on December 31 with the following message, however it appears to have been live yesterday (perhaps spammers have hijacked the domain!)

"It's been a case of a long goodbye as very little work has gone into maintaining ORDB for a while. Our volunteer staff has been preoccupied with other aspects of their lives. In addition, the general consensus within the team is that open relay RBLs are no longer the most effective way of preventing spam from entering your network as spammers have changed tactics in recent years, as have the anti-spam community.”

We concur with this and as of version 6.5 of SpamSentinel for Lotus Domino we no longer use DNS RBL checks.

Slashdot wrote a story on ORDB: Long-Dead ORDB Begins Returning False Positives
http://it.slashdot.org/article.pl?no_d2=1&sid=08/03/25/2124224

If you are experiencing this problem or note that email takes two or three minutes to be delivered after the initial connection by the sending server, please check that you do not have relays.ordb.org listed in your Domino server's RBL configuration. In fact, SpamSentinel will catch over 99% of inbound spam without the use of this feature and false positives will be reduced, so I would recommend disabling it entirely.