Does Your Host Fight Spam?
Virtually anyone with an email address knows what Spam
is, and has, perhaps, considered giving up the speed, convenience,
and simplicity of email because of it. Those who have their
own websites are more vulnerable than the average person
with a single work or home email address from their company
or Internet Service Provider. Email addresses visible on
a website can quickly become Spam magnets, as automated
programs, similar in form to search engine spiders, roam
the web, looking for addresses to which new broadsides of
Spam may be fired. Website hosting companies generally provide
their clients email accounts for use with their domain,
but are you with a host that provides those email accounts
with Spam and virus protection?
Local Blacklist Filters
Webmasters shouldn't need to seek out local filters for
their site's contact email addresses. There are a variety
of server level solutions a hosting company can offer to
protect their users from unwanted emails. A most basic step
is provision of a very rudimentary "blacklist"
functionality to their users, allowing them to prevent future
Spam emails from arriving from the same address. This type
of filter is virtually worthless in today's Spam environment,
though, as it is quite rare to see unsophisticated email
arriving from the same address multiple times. Spammers
have grown far more sophisticated than that. Blacklisting
functionality is only really useful in avoiding email from
other real people you don't particularly wish to hear from
anymore.
Keywords and Regular Expressions
More advanced server level Spam filters are available. A
small advance is accomplished using keyword filters. Keyword
filters merely check for instances of a certain string of
characters and deny the message if that string if found.
The core problem with keyword-only filters is they can "over
filter". Someone who puts "sex" on their
keyword filter will find receiving local news and event
announcements difficult if they live in a town named "Essex".
Some filters attempt to address this deficiency by using
"regular expressions" in order to build a sophisticated
rule set to prevent Spam from reaching your inbox. Briefly,
regular expressions are syntax rules used to identify certain
strings of text or numbers. These rules can be set up to
identify text patterns that are commonly used in Spam. They
can become quite complex, but, as with most any filtering
method, are not 100% bullet proof. Some filters that use
regular expressions come with a basic set that can be appended
by the user. Obviously this kind of feature is of little
use to someone not familiar with regular expressions.
Bayesian Filters
Currently the most sophisticated filtering methods use Bayesian
inferences. Bayesian filters take a large data set and determine
the probability a message is Spam based on its similarity
to previous Spam messages. The more emails that are processed
and flagged theoretically make the filter more accurate.
Services that provide filtering on an ISP or host level,
like Postini's "SpamAway", filter billions of
emails and provide the highest level of success and fewest
"false positives". SpamAway is already highly
intelligent about identifying Spam and doesn't require any
"learning" commands or examples be provided. The
online, browser based interface keeps flagged messages in
an easily accessible "quarantine" and allows the
user to check for any false positives. White list functionality
is provided to aide in the prevention of future false positives.
A hosting company offering such an advanced service takes
Spam and virus filtering for their customers seriously.
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