Tutor Tips from ... the Computer Tutor

4 December 2005

Spam Reduction

Spam (not the meat product that inspired the Monty Python sketch, nor the sketch itself) is unwanted, unsolicited commercial e-mail (See Tutor Tip: Spam, Spam, Spam, Spam ... ). There are a number of steps one can take to minimize the amount of spam received. Here are but a few.

Set Your Spam Filtering to "High"
If you are using a program such as Norton Internet Security (which includes Norton AntiSpam), you can adjust the level of spam filtering. Norton AntiSpam's filtering engine attempts to identify spam automatically by using your outgoing e-mail to determine your usual e-mail correspondents. Over time, you can more precisely train Norton AntiSpam to reflect your personal preferences for receiving e-mail by simply sending and receiving e-mail as you normally would. Consult the program’s help file for more information.

Many Internet service providers (ISP) filter spam before messages are placed in your inbox. Online e-mail access servers, such as Hotmail and Juno, have systems that automatically collect suspected mail and place them in Junk mail boxes, which are emptied on a scheduled basis.

If you have a domain (such as computer-2tr.com), your host may provide spam filtering before the mail reaches you. Tiger Technologies (which hosts computer-2tr.com) allows general “low” and “high” filter settings. Make sure that your spam filter setting is set to "High".

Report Spammers
Most ISPs have an e-mail address to use when reporting spam. Often it is abuse@(host_service). Tiger Technologies’ address is abuse@tigertech.net. Sonic’s address is abuse@sonic.net. Send the entire message when you are reporting spam, not just the address.

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Don't Use a "Catch-All Alias" Unless You Need it
 Many Web hosts offer a feature called a Catch-All Alias that, by default, accepts mail for any address ending with your domain name (e.g., @computer-2tr.com.) That's often convenient. It means that you can use new addresses without setting them up in advance, and it means you'll receive any misaddressed messages. It also means that if spammers simply guess at an address — for example, if they send a random message to "blahblah@your_domain.com" — the message could be delivered to you.

You'll have to decide for yourself if the tradeoff in convenience vs. possibly increased spam is worth it.

Always give a "disposable" e-mail address to strangers
 One way spammers get your address is by buying lists from unscrupulous companies. Because of this, you should make sure you don't give a permanent e-mail address to strangers.

Instead, create a "disposable" forwarding address for this kind of mail and give out that address to unimportant contacts instead. If you start receiving spam because someone sells your address to spammers, you can simply delete the forwarding address and start using a new one.

If you have a domain host, you can name one of your available mailboxes junque@(your_domain_name (e.g., junque@computer-2tr.com). If you have DSL service with Sonic, you are given 5 e-mail addresses. You can create a “dummy” account.

You can also get a free mailbox at Juno, Hotmail, Yahoo, etc., that can be used as a disposable e-mail address. Their spam filters will reduce the amount of junk reaching these addresses.

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Don't Put an Important Address on Your Web Site
 If you have a Web site, spammers can get your address by "harvesting" it from your own Web pages. If it's possible for someone to copy-and-paste an address from your Web page, that address will eventually end up receiving spam.

You can make sure this doesn't become a permanent problem by listing a "disposable" address on your public Web pages, as described above.

Another common technique is to use a paint program to make a picture of your e-mail address, and then include that picture on your page instead of using normal text for the address. Spammers use automated software that reads only the letters of normal text (not pictures), so this prevents them from seeing it. Keep in mind, however, that this may make it difficult for visually impaired visitors to find your e-mail address, because they use software that converts normal text to sound. If you make your e-mail address be a picture, be sure to include an alternate way for visually impaired visitors to contact you.

Use SpamAssassin if possible
 ISPs, such as Sonic.net, use SpamAssassin - an easy-to-use system that uses a set of rules to identify spam and flag it as such so that it is easily filtered. SpamAssassin evaluates incoming mail, looking for particular characteristics that are common in spam e-mails, and assigns points for every characteristic it finds. If a particular e-mail earns enough points when examined by SpamAssassin, that e-mail will be caught by Graymail and not delivered. SpamAssassin also includes a report of which of its rules were triggered by a marked message.

Graymail is a tool which intercepts all mail SpamAssassin marks as SPAM before it is delivered to your inbox. All mail caught by Graymail is stored on Sonic’s server for 7 days, during which time you can review them at https://sonic.sonic.net/membertools/graymail/. Graymail sends a nightly report of all messages it has intercepted to your inbox. If you see that a message has been improperly intercepted, you can use our convenient web interface to white list the sender and deliver the captured message to your inbox.

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