An electronic messaging system that reviews content of inbound messages, verifies elements of header fields, and initiates an action if Name (N) and Address (A) of From (F)_and Reply-To (R) elements of header fields match or do not match, those elements being NF=NR and AF≠AR, to protect recipients against inadvertent routing of their reply email to an imposter of the named From sender, thereby mitigating risk of recipients falling prey to what is referred to herein as “Reply-To Whaling” attacks, within the email security category of anti-phishing.