Since yesterday, March 25 ORDB.org – one of the old SPAM blacklist databases – started to blacklist all IP addresses. As a result, all mail servers using a spam filtering solution that still references ORDB (relays.ordb.org) started to immediately block all incoming e-mails. I got some reports into my personal e-mail yesterday, that finally got fixed by my provider today.
If you’re running MDaemon 9.60 or newer (released June 12, 2007) then MDaemon’s installer automatically removed relays.ordb.org from your spam blocker configuration, but if you’re on an earlier version you might want to double check your configuration.
To check to see whether or not you’re using ORDB, open the MDaemon GUI, go to the Security menu, look for either “DNS Blacklist” (in newer versions) or “Spam Blocker” (older versions), and see if you see any mention of “ordb.org” in your list — If you find it, select and remove that entry and you should be good to go.
Although ORDB.org was shut down on December 18, 2006, yesterday they changed their behaviour, and instead of timing out, they are blocking all IP addresses, that is, every e-mail server queried is being reported as an open relay — Depending on your configuration, this may result in all mail being blocked, or it may simply increase the chances that legitimate mail is treated as spam.