Spam-Fighting Tools
Spam: Unsolicited e-mail, often of a commercial nature, sent indiscriminately to multiple mailing lists, individuals, or newsgroups; junk e-mail. - The American Heritage® Dictionary of the English Language, Fourth Edition. Copyright © 2000 by Houghton Mifflin Company.
How Atomic Systems uses Real-time Blackhole Lists (RBLs) to completely block the worst spammers
RBL: a live list of the internet addresses which spammers and worms are currently using to deliver email.
The vast majority of all spam, worms, trojan horses and virii come from a single source connected to the internet, delivering the same message over and
over and over. Sometimes, this source is an open mail relay
and sometimes it is someone's personal computer which has been taken over by an email worm. Sometimes even, the source is a computer which the spammer has leased from an unsuspecting ISP.
RBLs shut down these spammers by making the address of their source computer known to the rest of the internet community. Once a spammer's source computer is identified to an RBL, everyone who subscribes to that RBL can now filter their email and dump all email coming from that source.
Atomic Systems makes use of several well-maintained, fair RBLs to filter out the bulk of the most obvious email coming into our systems. This filters out spam email automatically and prevents (at last estimated) about 80% of all spam arriving at our systems.
Use your mail program to filter out remaining junk email (spam), viruses, worms and trojans
If you need help getting your email program set up to filter out spam and virus-infected email according to our heuristics, consult us at 818-610-8447 and we can walk you through it.
Atomic Systems uses SpamAssassin to test all of its incoming email, subjecting it to a series of heuristics and producing a final "spam probability score." We never delete any email based on the results of these heuristics, as spam-detection can never be perfect; there are always letters which get marked as spam which are actually valid emails. The letters are simply "scored" and then delivered.
This score is added, along with other information, to the header of every letter coming into our systems. All modern email programs can filter email based on header values these days, so you can use this score to delete incoming spam email automatically, or simply move it to a "junk" folder for reviewing later, after you've read your non-spam letters. An example header of an email that contains the SoBig.F virus:
X-Spam-Status: Yes, hits=7.6 required=5.0
X-Spam-Level: *******
X-Spam-Flag: YES
As you can see, the letter scored a 7.6, which is the sum of many smaller values attributed to the email for certain characteristics such as fake return email addresses, containing executable attachments, etc., all of which added up to 7.6. Our system has a threshold of 5, which means that a score of 7.6 strongly indicates the letter is spam or a trojan.
Notice the score is also represented in the header field X-Spam-Level as a series of seven (7) asterisks. This allows you to filter out email coming into your email program using any threshold you wish. If you filter email using this header, and you wish to be more lenient, you could have your filter check for not 5 asterisks, as our system automatically does when it declares a letter as "spam" but perhaps 6, 8 or even 10 asterisks. The higher you set the number of asterisks to filter, the more spam you will get, but also the fewer "good" letters will accidently get thrown into the junk pile. |
