Douglas Otis wrote:
No, iprev would not be a good solution. The reverse IP address space
is poorly maintained which causes resource limited performance to be
reduced by an order of magnitude while waiting for the timeouts.
But iprev requires relaying of the IP address as part of its reported
output. So the header field would report:
Authentication-Results: <authserv-id>; iprev=<result>
policy.iprev=<ip-address>
You could, I suppose, use that to relay the IP address to an internal
MUA or filter in association with results from other methods, but that
isn't the intended use of iprev. That sort of thing remains out-of-scope.
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