Anti Spam Software
Spam blocker Filter
Anti Spam Software Bennett Haselton didn't realize at first that
his e-mail wasn't being delivered. While doing some routine maintenance,
the First Amendment activist noticed in September 2000 that not only
were his outgoing e-mail messages being blocked, but his Web site,
Peacefire.org, was unreachable by many Internet users.
Three years later, Haselton knows firsthand that the war against the
wave of unsolicited commercial e-mail -- spam -- that is paralyzing
computer networks worldwide is a messy one. It's a war waged not just by
the corporate giants who own the computer networks that make up the
Internet's backbone, but by little-known guerilla groups equally opposed
to junk e-mail. It's a war with lots of unintended consequences, as
Haselton found out when he learned that his e-mail problems were the
result of his organization being blacklisted.
Blacklists, also referred to as "block lists" or "blackhole lists," are
compilations of Internet addresses associated with known spammers. Many
are publicly available online, and system administrators often use the
lists to block all incoming e-mail from those addresses. Like black
holes, they are powerful and poorly understood -- and escaping their
grasp can be impossible. This has made them one of the most effective
yet controversial weapons in the crusade against unsolicited e-mail.
Haselton found out that his organization had been placed on the Mail
Abuse Prevention System (MAPS) list because of complaints that his
Internet service provider, Media3 Technologies, refused to cut off
service to companies suspected of doing business with spammers. MAPS
blacklisted a group of Media3's addresses, and ISPs using the MAPS list
blocked e-mail coming from those addresses -- including Haselton's.
Blacklist operators call this "collateral damage," admitting that it is
an unfortunate side effect. But for people like Haselton, who can go
unaware for weeks that their messages are dissolving into the ether,
collateral damage can seriously hinder someone's ability to communicate
via the Internet.
One problem that the unintended victims of blacklists frequently
encounter is that the people who compile them often keep a low profile.
As a result, it's hard for people whose service providers get
blacklisted to appeal. Sometimes, the only option for someone who gets
blacklisted is to change ISPs.
Even the most ardent spam opponents worry that the cure could be worse
than the disease.
"If you have a block list that stops 100 percent of spam and 75 percent
of legitimate mail, you've solved the spam problem, but you've created
another problem," said Ray Everett-Church, counsel for the Coalition
Against Unsolicited Commercial Email (CAUCE).
But harried system administrators, desperate to prevent spam from
crippling their networks, are more supportive of blacklists. They're the
ones who hear the complaints when their customers are buried in spam,
and it's their budgets that are tapped to foot the bill for the extra
bandwidth and computer space needed to house reams of unwanted e-mail.
The spam problem is so bad that every network administrator uses some
sort of blacklist to sort good e-mail from bad, according to Nate Shue,
a senior network engineer at Vienna, Va.-based software firm Industrial
Medium LLC.
Shue said the lists are more useful than spam filters because they block
offending e-mails before they reach the network. Blacklists are a more
efficient option than e-mail filters, which can keep most offensive
e-mail out of recipients' inboxes, but only after those e-mails have
entered a company's network. By the time the filter does its job, the
recipient has already paid the price of handling the message.
"The fact that someone has to hit the delete key is not what I'm
concerned with. You've already suffered the damage at that point," Shue
said.
Big e-mail hosts like America Online, Microsoft and Yahoo can afford to
develop their own blacklists, but smaller organizations typically rely
on lists published by groups like MAPS, Spamhaus and SpamCop.
Some administrators take those lists and install them directly at the
borders of their networks, while others, like Shue, use the lists in
conjunction with their own research to determine who gets blocked.
MAPS published its first blacklist in 1998, and dozens of groups have
released their own since then. Many are small-scale, volunteer-based
operations that let system administrators use the lists for little or no
charge.
One popular list created by SpamCop is compiled automatically based on
complaints submitted by e-mail users. To get off the list, e-mailers
must appeal to SpamCop founder Julian Haight. Haight acknowledged that
the system isn't foolproof. He deletes improper listings, but it's a
time-consuming process for one person.
One list -- the Spam Prevention Early Warning System, or "SPEWS" -- has
especially enraged e-mail marketers.
It is unknown who runs SPEWS, and the Web site -- spews.org -- offers
few answers. The site's registration information at various Internet
WHOIS databases is deliberately false, with the e-mail contact listed as
not@available.org.
The SPEWS site recommends that people who think they've been falsely
included on its blacklist direct their complaints to a newsgroup
available through Google. The site also makes it clear that posting to
the newsgroup won't help disgruntled bulk e-mailers get off the list.
"Only the discontinuation of spam and/or spam support will," the site
says.
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spam
The Goals of spam
The goal of spam
is to determine the intrinsic grouping in a set of unlabeled data. But
how to decide what constitutes a good spam? It can be shown that
there is no absolute “best” criterion which would be independent of the
final aim of the spam. Consequently, it is the user which must
supply this criterion, in such a way that the result of the spam
will suit their needs.
For instance, we could be interested in finding representatives for
homogeneous groups (data reduction), in finding “natural
clusters” and describe their unknown properties (“natural” data
types), in finding useful and suitable groupings (“useful” data
classes) or in finding unusual data objects (outlier detection).
For the latest information about
The Goals of spam
Who uses spam?
Many different types of organizations use
spam as a vital
part of the work. A sampling of these include:
-
Marketing:
finding groups of customers with similar behavior given a large
database of customer data containing their properties and past
buying records;
-
Biology:
classification of plants and animals given their features;
-
Libraries:
book ordering;
-
Insurance:
identifying groups of motor insurance policy holders with a high
average claim cost; identifying frauds;
-
City-planning:
identifying groups of houses according to their house type,
value and geographical location;
-
Earthquake
studies: spam observed earthquake epicenters to
identify dangerous zones;
-
WWW:
document classification; spam weblog data to discover
groups of similar access patterns.
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Anti Spam Software
