Using HP's Server Migration Pack to do migration requires three servers. The source, destination and the application server. If there is a firewall in between any of these servers, you will need to open some ports. Windows Firewall is automatically disabled when the migrations starts.
Ports required:
1. Between the source and the application server ports 1125 and 1126
2. Between the destination and the application server ports 1125 and 1126
3. Between the source and the destination servers ports 1126
Other requirements need to be fulfilled include iSCSI initiator 2.01 to 2.03 for the application server.
View the User guide here