Here are the ports that you’ll need to open on a firewall for replication.

The program uses the Server Message Block (SMB) protocol to copy files between two hosts. SMB-based communications use the following ports:

* 137 (TCP/UDP) -- NetBIOS Name
* 138 (UDP) -- NetBIOS Datagram
* 139 (TCP) -- NetBIOS Session
* 445 (TCP) -- SMB over TCP

With a default installation and network parameters, the program will attempt to connect to the remote host using TCP port 139. If you would like to force the program to use the newer SMB over TCP port (445), then you can disable NetBIOS over IP on the source system.

You can disable NetBIOS on a network interface by accessing the interface’s TCP/IP properties, clicking the Advanced button, then clicking the WINS tab, and finally clicking the "Disable NetBIOS over TCP/IP" radio button. With NetBIOS disabled, the program will automatically connect to the target system using TCP port 445. So you need to allow access through your firewall from the source system to the target system with port 445 as the destination.