Rsync uses default port 22 over SSH to communicate with remote host. Due to security purposes, most of the Linux system users changed the default SSH port to some non standard port. In that case you need to specify SSH port to connect rsync command on non-standard port.
Run Rsync with Non-standard SSH Port
You can specify the SSH as default protocol to use for Rsync communication between local and remote host. The following example will use SSH on non-standard port (2232) used by the remote host with rsync command.
-e "ssh -p 2232"SRC/ [email protected]:/DEST/