Opening TCP port 3389 from the Internet to your computer would probably be a bad idea as people aren’t necessarily looking for RDP connections on other ports.
So, it is a good security measure to change the port RDP listens in on to a different port, then enabling connectivity to that port through the firewall. In many cases corporate networks are watching traffic on ports 80 and 443. So change the RDP port to 444. Now, you via Terminal Services to an office computer for example by starting the Remote Desktop Client and typing in rdp.gregsoffice.com:444.
If you’d like to change your RDP port, navigate to HKEY_LOCAL_MACHINE\ SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp and change the DWORD value for PortNumber to the hex number for 444 (or any other TCP port value).