Email filtering is an essential task. There are many methods like:
=> Bayesian spam filtering
=> SpamAssassin/DSPAM programs
=> Check open relay using RBL etc
Now ORDB.org is shutting down its operation. ORDB is quite effective and I use this list against all of email servers. Spammers still use 3rd party servers and desktop computers so that they could minimize or avoid detection by re-routing their e-mail through these third party e-mail servers.
According to their home page:
We encourage system owners to remove ORDB checks from their mailers immediately and start investigating alternative methods of spam filtering. We recommend a combination involving greylisting and content-based analysis (such as the dspam project, bmf or Spam Assassin). DNS and the mailing lists will vanish today, December 18, 2006.
Generally, I use following sequence while configuring anti-spam
These services blocks thousands of spam everyday before hitting email server and Spam Assassin. Indeed a bad news for mail server admins!
🐧 Get the latest tutorials on SysAdmin, Linux/Unix, Open Source & DevOps topics via:
|Category||List of Unix and Linux commands|
|Firewall||Alpine Awall • 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 • cron • 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||Alpine • CentOS 8 • Debian 10 • Firewall • Ubuntu 20.04|