I'm newbie Zimbra installator. Had only some expereince with it from user side, years ago.
But now, flawlessly running and exploring my own test ZCS setup.
Before actual development integration in two weeks i want to approve some questions.

Is it ok to install Zimbra on production server before adding/changing MX record to my domains zone?
Because my company already has some crap mail server running on domain which i can't just shutdown while integrating new one. Downtime shiuld be minimal.
So which one is better:
1 install zimbra with manually entered domain name and only after running server with all accounts change MX record on domain.
2 add secondary MX record with low priority to domain zone

Second question:
How to install in DMZ? I want Zimbra with all it's services to be instal;led in DMZ behind firewall.
I have tried to search any similar howtos or threads but had no luck. Just forward all zimbra ports?

I will really apreciate any suggestion/waypoint regarding my questions.

Thanks in advance.