Birta Levente:
> Just curiosity: it's not unwanted to check postscreen_dnsbl for an IP
> which is blacklisted in postscreen_access_list?

Note: don't use no double negatives.

Wietse:
> That would be a waste of Postfix resources. It would make Postfix less
> resistant against abuse from a known-bad netblock.

Birta Levente:
> I'm sorry..not sure if understand: would be a waste of resources to not 
> check dnsbl even if is already blacklisted?

In fact, the action is configurable.

postscreen_blacklist_action (default: ignore)

   The action that postscreen(8) takes when a remote SMTP client is perma-
   nently blacklisted with the postscreen_access_list parameter.   Specify
   one of the following:

   ignore (default)
          Ignore  this result. Allow other tests to complete.  Repeat this
          test the next time the client connects.  This option  is  useful
          for testing and collecting statistics without blocking mail.

   enforce
          Allow  other  tests to complete. Reject attempts to deliver mail
          with a 550 SMTP reply, and log the helo/sender/recipient  infor-
          mation.  Repeat this test the next time the client connects.

   drop   Drop  the  connection  immediately with a 521 SMTP reply. Repeat
          this test the next time the client connects.

For maximal resistance use "drop". To learn what mail is blocked,
use "enforce".

        Wietse

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