Hi Neil. The incoming gateway must be set up on the backup server. For example, if you want the backup server to be the backup for the production server, add the IP of the production server to the Incoming Gateway section of the backup server. Also be sure to complete the rest of the set up such as adding secondary MX record to your mail domain's DNS zones which point to the backup server. I hope this helps.
Linda Pagillo
Mail's Best Friend
Email: linda.pagillo@mailsbestfriend.com
Web: www.mailsbestfriend.com
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