Email Security

Controlling the tide of junk and scam emails is a growing problem. When Halesowen College's commercially provided system could no longer keep up with the job they turned to open source software. With around 30,000 incoming emails a day, of which around 90% were junk this would prove to be a good test.

Anti Spam SMTP Proxy (ASSP)

The first line of defence is ASSP. This software sits in front of the server that handles incoming mail and turns away the most obvious junk. It performs analysis on mail headers and stops anything that is invalid. There are many standard checks that ASSP can perform and everything is tunable to your own needs.

Postfix

Postfix is an open source mail relay. In this set up it is used to stop mail that is being sent to invalid recipients before it is relayed to the central mail server, which avoids having to process the 'undeliverable' message which is itself likely to be addressed to an invalid address.

SpamAssassin

SpamAssassin is an open source mail filter which can work in conjunction with Postfix (and other mail servers) to identify spam and react the way you want. It has rules that are updated every day to keep up with the most common forms of junk mail.

ClamAV

ClamAV is an anti virus package released under the open source model. It has many uses but in this configuration it is set up to work with Postfix and SpamAssassin to identify scam emails, using the signatures (small donation appreciated) from Sanesecurity.

How well does it work?

It's not straightforward to analyse how well something like this is working, as what constitutes junk mail varies from user to user. However, our users are quick to let us know when they're getting mail they don't want, and the number of calls has gone from several a week to maybe one a month.Total cost not including time - £0, ongoing costs £0.