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:
Restart postfix mail server:
# service postfix restart
|Category||List of Unix and Linux commands|
|Firewall||CentOS 8 • OpenSUSE • RHEL 8 • Ubuntu 16.04 • Ubuntu 18.04 • Ubuntu 20.04|
|Network Utilities||dig • host • ip • nmap|
|OpenVPN||CentOS 7 • CentOS 8 • Debian 10 • Debian 8/9 • Ubuntu 18.04 • Ubuntu 20.04|
|Package Manager||apk • apt|
|Processes Management||bg • chroot • disown • fg • jobs • killall • kill • pidof • pstree • pwdx • time|
|Searching||grep • whereis • which|
|User Information||groups • id • lastcomm • last • lid/libuser-lid • logname • members • users • whoami • who • w|
|WireGuard VPN||CentOS 8 • Debian 10 • Firewall • Ubuntu 20.04|