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Old 11-01-2004, 11:33 AM   #1
Registered: Sep 2003
Location: Michigan
Distribution: Gentoo, Knoppix
Posts: 69

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Require PTR lookups for postfix

how do I setup postfix to require reverse DNS lookups to prevent some spam.? I did some googling, but couldn't find it.
Old 11-01-2004, 04:01 PM   #2
Registered: Sep 2004
Location: Texas, USA
Distribution: Fedora
Posts: 620

Rep: Reputation: 31
Check the postfix man pages: man 5 postconf

In particular:

Reject the request when the client IP address has no PTR (address to name) record in the DNS, or when the PTR record does not have a matching A (name to address) record.

The unknown_client_reject_code parameter specifies the response code for rejected requests (default: 450). The reply is always 450 in case the hostname lookup failed due to a temporary problem.


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