Better security
  Prevent address harvesting attacks.
  Protect against Denial of Service attacks to ensure stability of your messaging network.

Effective use of network capacity
  Optimize message flow into and out of your network.
  Reduce bandwidth and filtering overhead by rejecting unwanted messages before they enter your network.

Total control of network traffic
  Limit the number of connections based on a wide range of criteria.
  Throttle message flow based on connection source, message volume, message characteristics, time periods
        and other variables.
   Based on rule matches, email may be rejected, silently discarded, or deferred until a later time .
   Return tailored messages to senders on disallowed networks.
   Apply different limiting criteria at various times of the day.