As outlined in the requirements, Double-Take supports IP and port forwarding in NAT environments with the following caveats.
When setting up a job in an environment with IP or port forwarding, make sure you specify the following configurations.
Make sure you have added your server to the Double-Take Console using the correct public or private IP address. The name or IP address you use to add a server to the console is dependent on where you are running the console. Specify the private IP address of any servers on the same side of the router as the console. Specify the public IP address of any servers on the other side of the router as the console. This option is on the Add Servers page in the Manual Entry tab.
When choosing the target server for your job, you may be prompted for a route from the target to the source. This route, and a port if you are using a non-default port, is used so the target can communicate with the source to build job options. This dialog box will be displayed, only if needed, after you click Next on the Choose Target page in the job creation wizard.
If you are configuring network monitoring, make sure you specify the port to use for monitoring the Double-Take replication service. This option is in the job creation wizard on the Set Options page in the Failover Monitor section.
When specifying a network route or reverse routes for full server jobs, you can enter a public IP address and then specify ports for the Double-Take Management Service and Double-Take replication service. This option is in the job creation wizard on the Set Options page in the Network Route section or the Reverse Protection and Routing section for full server jobs.