Spam

Why am I getting spam?

Programs used by spammers scan through lots of websites looking for email addresses and add them to their lists. Since the something@dow.cam.ac.uk generic email addresses have been the same for several years, the addresses are on lots of spam lists.

Alternatively, the spammers may try a 'brute force' approach, trying every possible combinations of letters and numbers.

Protecting your email address

• Avoid putting your email address on webpages. Disguise it if possible, for example within Cambridge you can just quote the first part of your email address like spr32.
• Don't forward on chain emails. These are used by spammers to gather email addresses.
• Don't use your real email address to post on Usenet newgroups
• Don't bother trying to unsubscribe from spam lists. It rarely works and may just confirm that the email address is valid, inviting more spam.

The Hermes spam filter

A new feature on Hermes allows you to filter out junk email ('spam') so it doesn't clog your inbox. The system has been designed to make sure you don't lose any legitimate email.

See below for details, but here are the key points:

• to set up filtering, go to Hermes Webmail at https://webmail.hermes.cam.ac.uk/
• click on the Manage icon and then the Junk Email button.
• You can set a threshold level... the lower the number, the more spam will be stopped, but the more likely legitimate email will be classed as spam.
• Messages will be moved to a Spam folder where you can quickly scan them and then delete them in bulk.

Here comes the science bit

The Junk Email Filter filters messages based on how much they look like junk email (otherwise known as spam) according to a score that is computed by applying a large number of tests to each message and calculating an overall result. Since it isn't possible to decide on technical grounds precisely whether an email is spam or not, the score is heuristic: a higher score means the message is more likely to be spam.

You pick a threshold score above which messages are filtered to a separate spam folder, which you should check periodically (once a week, say) for misfiled email and to delete all the spam. The lower the threshold the more likely it is to misclassify a legitimate message as spam, so a score of 1 is likely to move genuine messages to your spam folder and a score of 20 is likely to leave spam in your inbox.

We recommend setting the threshold to 10 at first, and adjusting it based on how well it works for you. Note that the filter is most accurate for English email so if you exchange a lot of foreign-language email you will probably have to use a higher threshold.

Ignore and delete

Remeber the delete key is never far away. If you don't get too much spam, it's pretty simple to delete it. If you're upset by the content of a spam email, contact a JCR member.