Backup MX cPanel server with forwarding?


May 15, 2012
cPanel Access Level
Root Administrator
My main domain has been offline (null-routed) due to a DDoS attack for coming up 5 days now, host and hosts ISP both not happy. However this VPS is a mail server and because of this downtime 36k+ emails will bounce back, some will be saved by queuing but considering the amount of downtime, it's a loosing battle.

I need to know the best way to setup a secondary mx record and server so that when the main server comes back users can find their mail in their inbox. (Not for this time obviously, but I know my domain is a target and I need to be more prepared for next time).

What I have thought about so far:

- setup new WHM server on new server (server2)
- create new user, use account name and domain of server1
- rsync /etc/localdomains on server1 to /etc/secondarymx on server2
- point secondary mx record to server2's IP (with lower priority obviously)

What I don't know/understand is:

a) Is there anything else I need to do to get the secondary mx server working? (Perhaps rsyncing the /mail directory of the domain on server1 as well? [if so, hopefully just the directory structure, there is many many GB's of emails in there])

b) How do I get my mail back? When server1 comes back will it automatically forward emails back to the inbox of email accounts? If not, how can I set this up?