Better Blacklisting and Safelisting

Filed in by Rackspace Blogger | June 29, 2006 7:26 am

A couple of weeks ago we blogged about some of the improvements we’re in the process of making to our anti-spam system[1]. Today we released the first round of those improvements.
In this release, our safelisting and blacklisting systems got an overhaul. Previously, when users added addresses to their safelist, mail from that sender could still get blocked. This was because the safelist rules were used in the spam content filter part of our system (SpamAssassin[2]), but not in the Postfix[3] system that attempts to reject spammer SMTP connections. Also, mail from blacklisted senders would get tagged as spam and delivered to the spam folder, rather than getting blocked outright by Postfix.
Now all of this takes place within Postfix. Email from senders that are on the recipient’s safelist will never get rejected by Postfix, and email from senders that are on the recipient’s blacklist will always get rejected by Postfix.
Thanks to Mike T., our new anti-spam guru, for knocking this out.
Now we begin work on the next phase… letting customers add IP addresses to their safelists and blacklists. Stay tuned!

Endnotes:
  1. some of the improvements we’re in the process of making to our anti-spam system: http://www.webmail.us/blog/a/2006/05/why_am_i_getting_so_much_spam
  2. SpamAssassin: http://spamassassin.apache.org/index.html
  3. Postfix: http://www.postfix.org

Source URL: http://www.rackspace.com/blog/better_blacklisting_and_safeli/