Spam is flooding the Internet with many copies of the same message, in an attempt to force the message on people who would not otherwise choose to receive it. Most spam is commercial advertising, often for dubious products, get-rich-quick schemes, or quasi-legal services. Spam costs the sender very little to send -- most of the costs are paid for by the recipient or the carriers rather than by the sender.

At the very minimum, spam is annoying. It makes the tedious job of sorting through your mailbox take a little longer. Some spam is offensive: The get-rich-quick schemes offend your common sense, and the porn-site ads may offend your sense of decency. Spam wastes money and network bandwidth. People who pay for their connect time become enraged when they wait for a large message to download only to find they've been spammed. These outraged people respond angrily to the spam, not realizing that the return addresses are usually forgeries. The mail either bounces back to them (again wasting bandwidth), or worse, winds up in the in-box of the innocent person whose return address the spammers forged.

Two widely-used free services were once available to help ISP's filter spam. One of these, Open Relay Behaviour Modification System (ORBS) operated successfully until May of 2001, when it was successfully sued and shut down.

The other service, Mail Abuse Prevention System (MAPS) is still in operation. However, facing legal difficulties, MAPS ceased it's free services as of August 1, 2001.

In light of this, Deep Sky Technologies Inc. will begin utilizing it's own mail filtering software. Using spam sent in by customers, junk e-mails will be stopped at its source.

Follow these links for more information on Spam and what you can do about it.

• Mail Abuse Prevention System
• The Internet Abuse FAQ
• WDVL: Spam, Spam, Spam...
• Spammers do more than Spam
• Tracing Spam
• Norman De Forest's Spam Page

It's worth knowing how the perpetrators of junk e-mail come up with the e-mail addresses to send their messages to. There are several sources of mailing lists, but most of them originate as the return e-mail addresses attached to usenet postings in newsgroups.

If you post to usenet, chances are you'll receive junk e-mail sooner or later. Avoiding usenet entirely is one solution, albeit a fairly radical one. You might try not providing an e-mail address for your newsreader Ð this has the catch of not allowing people who wish to respond to your posts to get back to you personally. At least, this might be a catch. It might be a feature, too.

There are mailing lists about generated by software that automatically roams the web looking for e-mail addresses embedded in web page. This won't be a concern unless you have your own web page.

Spammers use Web-crawling robots and scripts that scan newsgroups to generate lists of email addresses. They then augment these lists with the names of legitimate subscription mailing lists in order to widen their reach. Once they have their lists assembled, any standard mailer software can be used to broadcast their message across the Net.

Spammers are fully aware that they annoy people, and know that their business would be jeopardized if their targets could fire back. If enough irate users were to complain to a spammer's ISP, the spammer's account might be cut off. In fact, many ISPs now have user agreements that explicitly forbid spamming. Even if the ISP takes no notice, the flood of return mail to the spammer could quickly make the account useless. For these reasons, among others, many spammers take pains to conceal their identities.

The next time you get a piece of spam, take a look at its headers and try to figure out where it came from. If you think you know, chances are you're wrong. The From: and Reply to: fields may be missing, or they may be something obviously bogus such as nobody@nowhere.com. Or it may look like a perfectly valid ordinary address. Don't be fooled. Most of the return addresses are forged.

Some spammers even take advantage of the free trial accounts offered by certain ISPs to fire off a few thousand emails and run before the ISP realizes what's going on.

It's easy to spam because the Simple Mail Transport Protocol (SMTP) makes it that way. Many, if not most, mail-transport programs are set up to run in promiscuous relay mode, meaning that they will accept and forward mail even if it's addressed to someone outside the domain for which the relay is responsible. A very simple script, or even a human armed with the telnet program, can connect directly to a machine that receives incoming mail for an organization and fire off a barrage of hard-to-trace letters addressed to recipients in some other locale.