We currently have one Exchange Server 2003 (Enterprise Edition, with Service Pack 2) setup and running on our network. A couple of months ago our old exchange server crashed hard and we had to build a completely new one and restore mailboxes from backup tapes. What we want to do now, in case something like this happens again, is to have a hot standby ready to go. We will be using Double-Take to replicate everything to the second server. My question is, do we need to purchase a second license for this other server? Or can we use the same license since its not technically "in production", and only becomes so when, and if, the first one goes down.