SpamAssassin Rule: <RCVD_HELO_IP_MISMATCH>
Standard description: HELO and IP do not match, but should
Checks if a HELO string is an IP, and if it is, that it matches the actual IP (or is in the same /24). (It doesn't fire if the HELO string is a hostname or private (RFC 1918) or trusted IP.)
The default scores for this rule can be found in the online list of tests.