I am currently setting up 2 A records for my Zimbra Server for some redundancy.

My 2 providers:

Deltacom - ip X.X.X.X
Cox - ip X.X.X.X

I want both of these ip address to point to my MAILSERVER.COM so I created 2 A records at Dyndns.com

ip X.X.X.X and ip X.X.X.X -> MAILSERVER.COM

I have configured the network card for both ip addresses. The only thing I am not sure about is whether or not I need to setup virtual hosting? Is there anything else I need to do to make this work?