You need to set up an additional server. But
You have to have registered another server from your other server before hand.
Admin client > Configuration tab >tools > registration > Register server
This will ask you for the server name / details / Id type / *note do not put a password in here (unless you have to)
Then once this is done place the server ID created some where you can get to it from the new server and then follow the instruction during the install for additional server.
You will task the New server to pick up the relevant Domino information from the live server (you can add Ip address here also). Then start the Domino server (if this completes OK).
Then setup your connection documents etc for replication etc and then do permissions for passthrough.