SpamAssassin Rule: CK_HELO_DYNAMIC_SPLIT_IP
Standard description: Relay HELO used a suspicious hostname (Split IP)
The HELO appeared to be suspicious. This is typically the result of a poorly configured email server advertising itself as XXX-XXX-XXX-XXX.hostname.tld (where XXX is an IP address).
The default scores for this rule can be found in the online list of tests.