I want backup my data through the Internet. If I setup the NAS behind a firewall and enable the Remote Replication function, which port I should open on the firewall rule?

Question:

I want backup my data through the Internet.
If I setup the NAS behind a firewall and enable the Remote Replication function, which port I should open on the firewall rule?

Answer:

Port 873 is used by default and is User configurable.