Created on 12-01-2004 12:00 AM Edited on 06-10-2022 01:37 AM By Anthony_E
Description
A DNS lookup on the 'A' record is performed on the information that is presented following the HELO or EHLO command from the SMTP client or server.
This information is usually a domain name, but may not necessarily always be the case.
For example, a mail client may send its IP address or PC hostname following the HELO/EHLO command.
The FortiGate unit simply performs a 'A' record DNS query on this domain name and if it fails to resolve, it considers the email as SPAM.
It does not attempt to verify whether the resolved IP actually matches that of the connecting IP.
