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Spam and how to deal with it

What is spam?

Spam is unsolicited bulk email - the online equivalent of junk mail. (The word "spam" is also applied to similar abuses of other electronic forums. As there is not much you can do about this other than using the forum's mechanism to report it, this page will concentrate on junk email.)

Your email address may be found from (among others) usenet postings, websites, mailing lists, or simply by guessing. Never reply to spam as either this confirms to them that they have emailed an active email address or if the real sender forged the from address of the email, your reply will go to an innocent victim.

Recognising spam

Much spam is obvious junk mail e.g. according to Wikipedia pharmacy ads make up 81% of all spam. However, spammers have an interest in making their messages masquerade as genuine email so that they will get past the recipient's spam filter. Sometimes this simply involves trying to fool the computer e.g. by putting the entire message in an image file so that computerised spam filters do not detect key words suggesting the message is spam.

When the spammer is also trying to trick you into giving them your account details, this is known as phishing. For example an email purporting to be from your bank, saying that your account has been disabled and asking you to follow a link and enter your username and password to re-enable it.

Criminals who phish for email account details frequently follow this up by sending more spam from these accounts. Often this takes the form of an email to everyone in the victim's address book saying that they are stuck in a foreign country and need money to get back home (the stranded traveller scam).

Dealing with spam

If you receive offensive email directed to you personally, see the UCS's advice on harassing email. Forward the message with full headers to You should not delete the messages because they may be needed as evidence.

There is usually no point in reporting ordinary spam as it tends to be sent from a forged address making it impossible to track down. If you receive a lot of unwanted email from the same address and don't consider it worth reporting, you can delete it automatically. Download a sample .forward file to your home directory and edit and uncomment the bottom section to get rid of the unwanted email.

Don't reply to spam.
Either you will be telling the spammer that your email address is live, or your reply will go to an innocent victim because the spammer sent their email from a fake address.
Don't follow links in spam emails.
The page they link to may be a copy of a website you use regularly, designed to trick you into entering your account details. If you think the email might be real, go to the organisation's website via your bookmarks or Google.
Don't open attachments you weren't expecting.
Viruses are frequently transmitted through email, and even if the message came from a friend, they may not realise that their computer has been infected. Save the attachment and scan it before opening it.
Don't panic about spam from Cambridge addresses or collateral spam.
Spammers almost always use fake addresses, and can forge email from any address they want. This means that you may receive spam appearing to come from a Cambridge address (even your own) or messages complaining that you sent a spam when you did not (collateral spam). Forging an email address is simple to do and does not mean that we have been hacked.
Don't forward virus warnings or chain email.
Real virus warnings will never ask you to forward them - however many hoaxes do. Viruses can also spread by emailing everyone in your address book and asking them to email everyone in their address book.

Spam filtering

Spam filtering means that a computer program automatically scans all your incoming email and files the ones which it believes to be spam into a separate folder, usually called "spam".

Most Maths accounts will have been set up with some form of spam filtering. For more details, and to adjust the threshold above which an email is considered spam:

Please check your spam folder regularly in case any real email has been mistaken for spam.