The native anti-spam controls in Sendmail and Postfix are quite similar. Patches can be installed against the regular qmail distribution, which implements many of the anti-spam functionality in Sendmail and Postfix. Each MTA has the ability to block messages based on local lists of IP addresses (and email addresses) as well as querying dynamic lists of IP addresses such as SORBS. Local, static lists of IP addresses and email addresses will only go so far in the fight against spam. The static lists can be used to exempt particular IP addresses from the dynamic lists. This enables the administrator to use the blackhole listing service but preserve access to required email servers that might be listed on the BLS.

There are many dynamic ...

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