Postfix and MS-Exchange Mail Server Affected by ORDB.org Spam Service

last updated in Categories Linux, Postfix, Sys admin, Tips, Troubleshooting, UNIX, Windows server

Since y’day I noticed one of our article related to ORDB.org spam blocker receiving lots of traffic. I received couple of calls from our clients because most emails was getting bounced via Exchange or Postfix mail server.

ORDB is now configured to return each IP as spam source

ORDB was a database of open relay email servers, provided until 2006 as a voluntary service to block spam. Now ORDB.org service has been re-activated and it is returning every IP address queried as being on its blacklist. I guess this was done to punish lazy sys admin / mail administrators 😉

If you or your mail server / gateway / firewall querying relays.ordb.org; please stop it immediately. If you query relays.ordb.org – mail server will rejecting all incoming mails from that server.

Symantec Mail Security for MS-Exchange Server – Spam Filter

Symantec Mail Security for Microsoft Exchange configuration in the list of Anti-spam blacklist servers including relays.ordb.org. Immediately remove the entry.

Remove ORDB.ORG from MS-Exchange Server Spam Filter

In Exchange Server 2003 you can find the feature for blacklist support within the global settings of your organization. Visit MS-Exchange System Manager > Global Settings > Message Delivery Properties -> Connection Filtering tab > Remove relays.ordb.org

Remove Linux / UNIX – Postfix Mail Server – Spam Filter

Open postfix configuration file and remove the following line:
reject_rbl_client relays.ordb.org,
Restart postfix mail server:
# service postfix restart

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

Share this on (or read 2 comments/add one below):

2 comment

    Have a question? Post it on our forum!