Improved spam mail filters at Cyberspace Ashram mail server - postfix mail configuration modified

After my last week's Hong Kong shopping trip - a total of 4 days in 14 hrs offline - I had exactly 6358 eMails waiting for download. That's a lot of eMails - but worst even - Busy Internet lines required a full 8+ hours non-stop download to get all eMail into my laptop. That definitely is far too much. Specially since I plan to return to a more quieter life in provincial areas in future months. Using mobile 3G connection hours of downloading mostly SPAM certainly is far too costly in time and resources.

Thus a need to further improve server side SPAM filters was / is needed. Thus far all of my spam filtering is done by spam assassin on my local machine. That requires all eMail to be downloaded. On a laptop always online that makes little difference in overall connection performance. With an average of far more than 1200 eMail per day and a planned online time of only a few times a short period per day or week. Hours of spam download needs to be avoided.

Hence as of this hour I have added improved spam filtering server side to reject reception of commonly known SPAM on server side before receiving the eMails into my mail server. That should reduce the overall mail traffic to be downloaded substantially. Several blacklists are available fur such spam filtering using common mail servers such as postfix. Currently I use for testing zen.spamhaus.org, other blacklists may be added as needed depending on results of the current zen.spamhouse.org filter results. An alternate possibility might be the use of spamassassin server side.

To avoid your eMails being lost - make sure you use proper precise subject lines and real content. As soon as several test days are successfully completed, I may post some results and details of postfix milters in current use for those wanting to improve their own server side spam filter procedure. If you have your own postfix server, you may want to have a look at the many highly efficient smtpd milters available for postfix. For newbies: milter is the correctly spelled word for mail filter commonly used in technical documentation!

God bless

hans