February 9, 2004
What can you do about spam?
By Tim Stephens
Communicationms and Technology Services (CATS) activated the Spam Assassin
spam-filtering technology on the campus mail server last year.
|CATS staff decided not to
block messages identified as spam at the server after conducting
a survey of campus computer users, said systems manager John Hammond.
To take full advantage of this service, individual computer users
need to configure their e-mail programs to filter out the messages that
the server identifies as spam.
Detailed instructions for how to do this are available at "CATS
Spam Filter Tools."
Additional information about CATS spam-filtering services is available
CATS staff decided not to block messages identified as spam at the
server after conducting a survey of campus computer users, said systems
manager John Hammond.
"The consensus from the survey was that getting a handful of spam
is not nearly as big a deal to people as missing a message that they
want to get," Hammond said.
Spam Assassin assigns scores to each message indicating the likelihood
that it is spam. Users can vary the threshold at which messages get
filtered out. The trick is finding the right balance between filtering
out as much spam as possible and not filtering out important messages.
And some spam will inevitably get through the filters, because the spammers
are constantly adapting to the filter technology.
"Filtering technology often tags legitimate e-mail messages and
fails to label some spam," said Arthur Keller, visiting associate
professor of computer science.
"I get several hundred spam messages a day. Without the two levels
of spam filtering I use, it would be hard for me to read my e-mail.
But I still have to scan the messages labeled as spam for the occasional
legitimate e-mail message I would otherwise miss," Keller said.
Some mailing lists and e-mail newsletters that people want to receive
will always be identified as spam. It is not difficult, however, to
set the filters so that messages from specified sources are allowed
through (instructions are included on the "CATS Spam Filter Tools"
web site referenced above).
Hammond said CATS regularly upgrades the mail applications on the campus
server, and future upgrades should lead to significant improvements
in the ability to counter spam.
The latest versions of some e-mail programs--including Eudora 6.0 and
the version of Apple Mail that comes with Mac OS X--have built-in spam
filters that users can "train" to recognize the mail they
do and do not want to receive.
In addition to using the available filters, other recommendations for
minimizing the amount of spam you receive include the following:
Never respond to a spam message in any way. Doing so
only generates more spam, because it confirms to the spammer that e-mail
sent to your address is actually being read by someone.
Limit the visibility of your e-mail address. Your e-mail
address can be harvested from a variety of sources, including web pages,
newsgroups, and mailing lists. Unfortunately, many campus faculty and
staff need to make their addresses available on campus web sites, where
they are vulnerable to harvesting by spammers.
Hammond noted that security measures to protect your computer from
hackers and viruses also play a role in combating spam. Spammers often
send their messages from other people's computers to disguise their
identities. In the latest twist, they appear to be using viruses to
transform infected computers into spam-sending machines. CATS maintains
a web page with information
on computer security.
Like other campus computer experts, Hammond is guardedly optimistic
about the prospects for controlling spam.
"I think our efforts can make a significant difference, but at
the same time I am certain that spam is never going to go away,"
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