Good morning, A bit of an extreme example, but i've often wondered, when looking through my Postfix logs, why some senders do this:
Received: from mx-out.facebook.com (outmail019.snc7.facebook.com [69.171.232.153]) by ..... The connecting host has HELO'd as 'mx-out.facebook.com' If it is traced through in DNS: mx-out.facebook.com: 69.63.179.26 69.63.179.26: mx.snc1.tfbnw.net. mx.snc1.tfbnw.net 67.231.153.30 67.231.153.30 mx0b-00082601.pphosted.com. mx0b-00082601.pphosted.com. 67.231.153.30 What I find a little crazy is why this bears no relationship to the connecting IP, and its reverse DNS: 69.171.232.153 - matching, as shown, outmail019.snc7.facebook.com I'm just wondering as to what circumstances would lead to a host HELO'ing with a hostname that differs from the connecting IP and host. I'm sure it is perfectly legal, but I don't see the logic?
