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With so much anti-spam software on offer, it can be a daunting task to find
the right spam filter for your company. At first glance most spam filters seem
to offer the same features; DNS Black lists, heuristic analysis, header
filtering, Bayesian filtering and black and white lists. However don't be
misguided by appearance. There are important differences between spam filters
and you should be aware of these before making your decision. Before selecting
your anti-spam solution, ask these 5 questions:
- Is the anti-spam software user-based?
Many anti-spam
products do not offer user-based spam filtering. User based spam filtering can
be useful if you want to exclude certain email addresses from being spam
filtered, or you only want to configure challenge/response for certain
mailboxes. In addition user based spam filtering allows you to handle messages
differently per user or group. Some users might prefer to have their spam
messages in their junk mail folder whilst others prefer to received them
tagged in their inbox.
- Can users view their own spam mails and update black & white
lists?
You do not want your Administrator sitting all day
reviewing all the quarantined messages and updating your white and black
lists. It is much easier (and more efficient) to let your users review their
own spam mails since they know best what is spam and what is legitimate. For
instance, an investment newsletter might be legitimate for one user and spam
for another.
- Does the software offer detailed message tracking?
Make sure that the spam filter provides adequate tracking of messages. In
order to fine tune your spam filter it is necessary to be able to find out why
a message was considered spam or legitimate, right down to the actual words
found in the message.
- Does the software provide bandwidth & storage savings?
The spam filter should have the possibility to reject messages
before they are received. For instance by checking DNS Black lists, Sender
Policy Framework and invalid recipients, spam messages can be blocked even
before they are downloaded, saving valuable bandwidth and storage space.
Actually since these methods catch the bulk of spam, you could cut down on
more than 60% of spam before it even reaches your server.
- Does the software allow you to handle spam messages according to
spam certainty?
Most anti-spam programs have a layered approach,
using many different methods to determine whether a message is spam. However,
does the spam software allow you to decide how to handle spam according to
each method, or is all spam handled in one way? Taking a granular approach to
spam improves efficiency and allows for early detection of false positives.
For instance if a message is clearly spam, e.g. it is not addressed to a valid
recipient or the IP address is listed on a DNS black list, there is no use in
forwarding these messages to the user's junk mail folder. Since these messages
can be considered spam with 99.99% certainty, these messages should either be
rejected or placed in a quarantined folder that gets cleared automatically
after a number of days. It would be a waste of your user's time to sift
through these messages. However messages that have been flagged as spam by
searching for words in the email are more likely to trigger false positives.
These messages must be forwarded to the user's junk mail folder for further
review.
See how Policy Patrol measures up:
- Is the anti-spam software user-based?
Policy Patrol
allows you to exclude mailboxes from being anti-spam checked and also allows
you to handle spam differently according to user or group (note that this does
require a Policy Patrol Enterprise license).
- Can users view their own spam mails and update black & white
lists?
Yes Policy Patrol can forward spam to the user's junk mail
folder so that they can view their own spam mails in Outlook. In addition you
can configure public folder agents that Policy Patrol uses to scan mailboxes
and public folders for email addresses to be added to black lists or white
lists. In this way users can drag and drop emails to add addresses to white
lists or black lists or to add messages to the Bayesian legitimate or spam
databases.
- Does the software offer detailed message tracking? Policy
Patrol provides detailed tracking of messages, showing each message that was
received (or sent) through Policy Patrol and what happened to it. For each
message it shows exactly which condition caused the message to be flagged as
spam, right down to the actual words found in the message.
- Does the software provide bandwidth & storage savings?
Policy Patrol can drop the SMTP connection if an IP is listed on
a DNS Black list or the email does not contain any valid recipients, providing
valuable bandwidth and storage savings. Policy Patrol can also use the Sender
Policy Framework to verify IP addresses and domains. If SPF returns a hard
fail, these messages can be rejected as well.
- Does the software allow you to handle spam messages according to
spam certainty?
Policy Patrol offers advanced granularity,
allowing you to specify for each method how spam messages should be dealt
with. For instance with Policy Patrol you can reject messages with IP
addresses on DNS Black lists, delete messages with URLs from SURBL lists and
forward spam messages with spam words to the user's junk mail folder. This
means that you can increase efficiency whilst reducing the risk of unnoticed
false positives.
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