To set up a primary and secondary back end mail server for Canit to route first go to the WebUI page Setup->Domain Routing.
- - Enter the domain and press Submit.
- - You will be prompted for the IP address(s) of the server(s). Enter the primary first and then the secondary on the next line. Canit will try the first until it's successful or gets a failure to connect then checks the next one in the list.
- - Leave "Treat route entries as MX records" as No.
- - Set the port (will probably be 25).
- - Press submit.
- - Repeat for all domains.
For future reference, on almost all pages for the WebUI there is a button in the upper right which will take you to context sensitive help from the manuals for that page.