Screen sharing between a Mac and PC on different networks

Discussion in 'macOS' started by cheezebob, Jan 16, 2008.

  1. cheezebob macrumors member

    Jun 27, 2007
    I tried sharing a PC's screen with my MacBook Pro with Leopard. The PC had TightVNC installed. I could only share the screen when both computers were on the same wireless network. When they were on different networks, screen sharing didn't work. Can I get it to work? Or is that kind of screen sharing only an iChat, Mac to Mac thing.

    Sorry my question might be boring and not about MacWorld..but can anyone help?
  2. Justinerator macrumors 6502


    Jun 26, 2007
    Redondo Beach, CA
  3. TheStu macrumors 65816

    Aug 20, 2006
    Carlisle, PA
    Well, can the two machines see each other? As in, can you share files between them?

    If you can, then that is a good sign. If you can't then you may have to set up a routing table on your router, so when a request on port XXXX goes out intended for 192.168.X.X, it gets first sent to the other router, then, on that router, the incoming requests gets routed to the other computer.
  4. cheezebob thread starter macrumors member

    Jun 27, 2007
    No I can't share files between them. I'm saying..say I'm in college on my Mac..can I screen share my mom's pc at home - many miles away - to help her battle the shortcomings of Microsoft Word? I can do that with 2 Macs using iChat, but how about one Mac and one PC? How do I set up this router table?
  5. ab2650 macrumors 6502a

    Jun 21, 2007
    The easiest way would be to set up your mom's router to port forward (NAT) TCP port 5900 to whatever her internal IP address is. Then you open a VNC connection to her external IP address and it should connect.

    A slightly more advanced setup, and way more secure, would be to to turn on a SSH server at home (simple if she were using a Mac, unfortunatly with windows it's additional software) and NAT port 22. Login with ssh and forward local port 5901 to her internal address and port 5900. The ssh command would be:

    ssh -L 5901:her.internal.ip.address:5900 username@her.external.ip.address
    Then connect your VNC client to "screen 1" (aka, port 5901) to "localhost" and it should tunnel over SSH securely.

    Yet another method using VNC is to issue a reverse connection, which would be useful if you have access to your router but she does not - However, it sounds like since you're on a school's network and she probably has a cable/DSL connection, she has more flexibility than you. I'll save how to do a reverse VNC connection unless you find you need it.

    The final method with VNC is to use an intermediary host to pass data to, e.g. a webhost account like dreamhost that has ssh access. It would require that both computers have SSH clients, which is built in to OS X, and a simple download of PuTTY for Windows. In this method, she connects to the remote host and forwards a remote port to her internal address and port 5900, you can then forward a local port from your machine when you connect and connect VNC again to localhost. I personally use this all the time to get past an aggressive firewall at work.

    There are probably lots of other screen sharing apps out there with simple setup, but VNC is a great tool. Combined with SSH it becomes damn secure, and you can do things like password-less logins with public/private key; Essentially you can make a script that your mom can double-click when she needs your help.
  6. richard.mac macrumors 603


    Feb 2, 2007
    51.50024, -0.12662
    try looking here for info.

    that thread was made before Leopard so you dont need to install a VNC client on your mac. and make sure that port 5900 is open on your router and Windows firewall.

    you will have to constantly check you external IP using or something else as it constantly changes unless you have a static IP. you can usually get a static IP from your ISP if they support it at an extra cost. then open "connect to server" (command-k) in the finder and type in "vnc://your PC's external IP"

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