Customers find that adding Email Reputation Services to their anti-spam solutions
has an exponential impact on offloading existing filtering solutions. What can appear
to be only
a small increase in blocked connections can translate into a large reduction of actual
messages
entering the filtering portion of their email infrastructure.
Translating blocked connections into blocked messages is more involved than simply
applying a
1:1 ratio. Studies show that while legitimate sources average slightly more than one
message per
connection, each connection from a spam source contains, conservatively, an average
of 1.6
messages.
It is far more efficient to reject spam at the connection level rather than take each
message
through full anti-spam scanning.
Connection Blocking and Scanning Requirements
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Connection Blocking Requirements
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Scanning Each Message Requirements
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The initial portion of the SMTP handshake
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The full SMTP-handshake
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A DNS query
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Complete message parsing, putting strains on computers that run anti-spam solutions
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