School of Computing

E-Mail Spam and Virus Checking

Introduction

We are now spam checking all email delivered to the Computer Science servers (myrtle, raptor). This involves checking the mail to see if it appears to be spam (unsolicited bulk email), and then marking suspect spam as such in the headers. That is all the system does; it does not delete messages and it does not change their content.

To take advantage of our spam checking you will need to configure your mail client to act upon the spam headers, or tell the mail delivery system to treat messages marked as spam in a different way. If you do not do this then your email will be unaffected by the spam checking.

This system only works if your mailstore is on a School of Computing server. If your mailstore is on another machine, such as Live@Edu, this documentation will not apply to you. You can change your mailstore to the relevant School of Computing machine if you have a login on one of them. The mailinfo tool can be used to change your mailstore - check the manpage for details.

New for 2004/2005

For the academic year starting in September 2004 we have introduced an improved spam checking service. This runs on dedicated spam checking servers using the latest version of SpamAssassin.

The most significant change is the new configuration tools. Under the old system you had to edit a file on a Unix system, whilst the new system lets you use a webpage or an interactive command-line tool. The command-line tool is called saconf and can be found on all our Unix servers. The webpage can be found over here.

Users wanting to import their old configuration into the new system should run the following command on their Unix server:

saconf ~/.spamassassin/user_prefs

Please also note that the user mailstore under the new system will be listed as comp-sci. Don't point your mail client here, keep using your existing server.

Please Note

No system that detects spam is perfect. There will be spam messages that the system will fail to detect, and occasionally genuine email messages will be flagged as spam. If you are not prepared to accept this then you need read no further!

Filtering Spam

The system installed on the School of Computing servers uses a program called SpamAssassin to decide whether an email message is likely to be spam and then adds extra headers to the message. Any message that SpamAssassin thinks is spam contains the extra header :-

  X-UKC-CSSpamCheck-Flag: YES

Armed with this information, you can then configure your email client to refile suspected spam into a separate folder. Here's how you do this for

Another approach is to persuade the mail delivery system to refile likely spam into a different mail folder as part of the delivery process. Details of how to do this can be found here.

Filtering Viruses

Computing Service perform virus testing on email before it reaches the School of Computing systems - any viruses will be removed before they reach your inbox. However, you may want to filter out the emails that contained viruses to a different folder. To do this, you can follow the relevant rules for spam checking but search for the following header instead :-

  X-UKC-Mail-System: Virus detected

You probably want to filter them to a different folder than spam, we'd recommend putting them in a virus folder. It's important that you look in your virus folder as it's quite possible legitimate emails may have attachments removed that look suspicious.

Configuration

We now provide a web configuration tool for spamassassin. This tool allows you to change the basic settings that the majority of users require. Follow the link below to log in.

For more advanced users, and users familiar with Unix we have a command line tool that allows full configuration of SpamAssassin. This tool is called saconf.

Now Your Spam is Filtered

Don't forget to check the contents of your spam folder on a regular basis, as the system will file regular email in there from time to time; that's a fact of life. For the same reason, please don't configure things such that suspected spam is automatically deleted. If you do so, then you will eventually lose something important.

More About SpamAssassin's Added Headers

More information on the headers inserted by SpamAssassin can be found here, and more information on SpamAssassin can be found at the SpamAssassin web site.

Help me!

If you have any problems, or if you think something odd is happening to your mail, please email us. Our address is cs-syshelp@kent.ac.uk. We will be able to help you figure out what is going on, and hopefully be able to fix it.

School of Computing, University of Kent, Canterbury, Kent, CT2 7NF

Enquiries: +44 (0)1227 824180 or contact us.

Last Updated: 17/09/2014