> you can set cloudbox as your domain's MX with a lower priority than homebox.
This is one way to do this, but if you do, remember that a spamming tactic in the past has been to direct spam to the lower priority MX records as often they were somewhat forgotten and not kept up with the latest spam guards.
Basically, always make sure your primary and secondary mail servers have the same and latest of whatever you are using to stomp on spam.
You will also want to change the length of time things are held in the queue. The default is something like 7 days. That might not be long enough if you're using the secondary MX as a failsafe.
This is one way to do this, but if you do, remember that a spamming tactic in the past has been to direct spam to the lower priority MX records as often they were somewhat forgotten and not kept up with the latest spam guards.
Basically, always make sure your primary and secondary mail servers have the same and latest of whatever you are using to stomp on spam.
You will also want to change the length of time things are held in the queue. The default is something like 7 days. That might not be long enough if you're using the secondary MX as a failsafe.