We recently migrated our exchange mail server to new hardware with a new name. The new mail server took on the interanl IP address of the old mail server so we did not need to change any routing at the firewall. We have not had any issues sending email until recently one of the users received the following error message:
Remote Server returned '550-Your message was rejected by this user and was not delivered. 550-Reason: Your IP address [220.127.116.11] appears not to be an email server. 550-Protection provided by: MagicMail version 2.0 550-For more information, please visit the URL: 550-http://www.linuxmagic.com/best_practices/check_dynamic_reverse_dns.html
550-or contact your ISP or mail server operator. 550 e8cb91a0-6fff-11e4-b560-ab
In the message it states that the IP address 18.104.22.168 is not a mail server and that is correct. Where did this IP come from?