Preventing Spam

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E-mail that is received but not wanted. Many people get very little spam and do not realise how fortunate they are. They probably have an email account with Sympatico, Cogeco, Rogers, Gmail, Yahoo, Hotmail or other large ISP. These companies go to a lot of trouble to minimize spam for their customers.

If you use Hosting by Cobourg Internet, then you will automatically get "Mail Scanner" which does a reasonable job of eliminating Spam. The hard part of course is recognizing border line Spam. Mail Scanner flags "in between" emails with {Spam} in the subject so it can be looked at by the recipient. See below for some of the Spam identification techniques used. However, not all spam gets stopped and some wanted mail never makes it through.

If you still get spam, there are some things you can do.

SPAM Prevention techniques

  • Minimize the number of people who have your e-mail address. If someone has your address in their address book and they get infected by a virus, then your e-mail address could be all over the Internet in minutes. The fewer people who have your address the less the chance of this happening. The catch is that we all like to get e-mails so this is not a good solution.
  • Don’t give your e-mail address to someone who will put it on a web site. Even if there is no virus involved, there are people who “harvest” e-mail addresses by searching web-sites for e-mail addresses. [More here]. They then collect them and sell them as a mailing list to spammers. 
  • If you must do either of the above, then either implement Spam management techniques (below) or use expendable addresses. For example, use a hotmail or Yahoo address and change it every few months. Then give these addresses to everyone except a very few.
  • If you get a SPAM message from someone who is not a highly reputable organization, do not reply at all. Do not even click on their link that says “click here to unsubscribe”. If you did not subscribe in the first place, this action will only signal them that you are silly enough to answer so you’ll get more SPAM. Conversely, for organizations like Sears, Staples, Future Shop, Globe and Mail, etc, if you don’t want their e-mail, you should unsubscribe. These and other reputable organizations can be trusted to stop e-mail if requested.
  • Hoax emails are in effect spam - they are unwanted emails. So before sending them on, be sure it's not a hoax. More.

Once spammers have your email address, you need to reduce spam's nuisance value.

SPAM Management techniques

Option 1
Use the SPAM management tools in your e-mail program. These vary considerably but the following can be used for Outlook Express 6. Others will be similar.

Select Tools>Message Rules>Mail… to set up a Mail “Message Rule”.
Here are instructions to set up a typical example:

  1. Select the Conditions…, select “Where the Message Body Contains Specific Words”
  2. Select the actions…, select “Move it to the Specified Folder”
  3. Rule Description, click contains specific words and under “Type specific words…” type (e.g.) Viagra and click Add then OK. Now click specified and click (if this is the first time you are doing this) New Folder – then type Spam to name the folder. If this is not the first time, select Spam. Then click OK.
  4. Name of the rule, enter a name - e.g. Rule 1.

Now click OK. You have now created a single rule – if mail arrives with Viagra in the body of the message it will be moved to the Spam folder. You can then look at this folder occasionally to make sure one of your friends did not send an off-colour joke. Then delete all these Spam messages.

Option 2
Use another e-mail program that has better spam filtering.

  • Outlook (available with Microsoft Office) – more powerful than the Outlook Express version but otherwise similar. Will import address information from Outlook Express.
  • Thunderbird e-mail – free – this works quite differently but manages spam well.

More on e-mail.

Option 3
Use a SPAM filtering service. Note that the risk is that you'll either get Spam still or you'll miss clean mail or you'll have to sort mail in a "Junk-mail-box". Some examples:

  • Eagle – includes Barracuda’s spam filter as part of its Internet service. Works well except it is prone to false positives - that is, it stops email you want.
  • Use an external service like OnlyMyEmail - Your incoming mail goes via their service and is forwarded to a new account. Externally, the world sees up to three e-mail accounts. Similar to Barracuda except that you can set it up yourself. Price is $36.00US per year.
  • Use email provided by CobourgInternet - all email accounts on sites provided by Cobourg Internet that use Cobourg Server include Mail Scanner which deletes bad spam and labels marginal spam.

Harvesting E-Mails

If you have allowed a web site somewhere to list your e-mail address, then someone else will find it (and others) and sell the list to someone else who will then send you Spam. The automated process to do this is called harvesting. This can be slowed down by using methods to disguise the e-mail address using scripts and/or graphics to show the address (such as done on this site) but sooner or later your e-mail address will find its way to a spammer. You can minimize the chances of this happening by the following:

  • Don't allow your email address to go on the Internet (e.g. web site) unless you know that the web site designer has disguised the address (like on many Cobourg Internet sites).
  • Change your e-mail address every 6 months or so (a pain).
  • When sending emails, if you don't know all the recipients personally, can you trust them to not sell or give away their own list of addresses? So in this case, send mailing lists to bcc (instead of "to" or "cc") to hide all addresses except the recipients own.

Hoaxes

If you have e-mail, sooner or later you will get a message that says something like:

"Believe it or not, there is a new Virus that cannot be stopped by Norton. It is really bad, it wipes out your hard drive."

It will often include a reference from Bill Gates, Microsoft or some credible sounding person or company who has issued a warning. It will then tell you what you have to do to "fix" the problem. These fixes are sometimes benign and sometimes cause damage of their own. The hoax message will nearly always beseech you to pass the message on to everyone you know. These kinds of messages are nearly all hoaxes. (I've seen many and there have been no real ones yet!) Knowing the sender is no guarantee they are legitimate. All the hoaxes I've received have come from well-meaning friends.

There are other hoaxes that purport to let you know about a health problem that you just have to know from an important sounding doctor. These sometimes contain some truth but other "facts" are just plain wrong.

The hoaxes cause little harm except clogging up the e-mail system. But it is embarrassing when you find out after you've forwarded a hoax to everyone! To see more on hoaxes, either now or next time you get an e-mail that's probably a hoax, click here. Hoaxes are also usually listed at Symantec (and other security companies). Go to their Security Response page. At the top is a search box. Enter some identifying text from the suspected e-mail (e.g. FREE M & M's) and click "Search". If it is a hoax, the response will confirm that and give details.

Hoaxes can often be half-true or sent willingly by people - e.g. "Stop the tax on e-mail with Bill 602P" which was never proposed but discussed at length on the Internet since 1999. For more on these kinds of sites, see Snopes. They also cover stories that may be true but seem unlikely. Another good source of information on hoaxes is at about.com.

Another form of Hoax that is more dangerous (financially) is Phishing. See security page.

Spam filtering techniques

A full analysis of spam fighting tecniques cannot be given here, because even if I knew all the tricks, it would be best not to make them public so spammers would know what was being used against them. But some are well known:

  1. Identify spamming email servers. When spam email is detected, the IP address of the email server can be identified. If this source continues to send spam, it will be blacklisted. Then other legitimate servers do not accept mail from them. Occasionally, servers get blacklisted when they should not have. Because a server may be shared by several sites, it is in everyone's interest to not allow spammers on their server or several sites could get "turned-off" to stop the one spammer.
  2. Look for combinations of words, subjects and unusual characters that are often used in spam. These may not be just the words you think - they may be (for example) too many uses of "bargain".
  3. Multiple emails from the same person in a short time - the exact number varies but this is why personal email accounts cannot and should not be used for large volumes of email (e.g. a club newsletter - usually up to 50 is safe and even maybe 150). A business account from an ISP will generally have a much higher limit - or maybe no limit.
  4. Too many links in an email - especially in conjunction with other indicators.