VNC, Over The Internet (Advanced)

DISCALIMER - If you don’t want to risk messing up your router, I suggest you stop reading now. If you understand about TCP ports and configuring routers, you’ll probably be ok. Oh, If you do mess up your router, I’m not responsible, I’m only providing this to people who want to try it and no ones forcing you to do it. Thanks.

Ok, So last time I mentioned VNC (If you haven’t read it I recommend you do so now, here’s a link).VNC is an amazing technology that allows you to control another computer from your own. It’s simple enough doing it over the home or work network. But what about doing it over the world wide web.

The problem with this is that it’s a bit more difficult to setup and maintain than normal VNC. If you have .Mac I’m sure you’ll know or a feature called ‘Back To My Mac’ which effectively does just what we’re doing what we’re going to do now, it’s just a bit easier becaue it automates everything for you, the only disadvantage is that it’s expensive (you have to pay for the .Mac membership) and it only works with Mac computers, sorry windows users like me. The advantage with this is that all the extra stuff is completely free and once you get the gist if it it takes little or no time to set up.

There are some things you will need before we even start to think about the Internet part. First you will need the software I mentioned in the last blog post, you will also need the WAN (Wide Area Network) IP address of your router, this is the IP address that your particular router is recognised as on the Internet, so if you have this number you can connect to it from anywhere. A good start is to set up the computer you want to connect to with the software and give it s static IP address, this effectively means that instead of the router automatically assigning the computer a new IP address every now and then, it keeps the same one. In Mac OS X, this is simple. Goto System Preferences, then to the network icon, then click the button that says advanced a box will then roll down with tabs across the top, click on the one that says ‘TCP/IP’ and in the list box where it says ‘Configure IPv4:’ select ‘Using DHCP with manual address’. Then you can input the number you want just below that with ‘192.168.1.xxx’ replacing the x with numbers (Be sure that no other device on the network has the same IP address or this isn’t going to work.

Right, So You’ve got the server setup with the software and the static address on the network, now comes the tricky bit. You now need to configure your router to do something called ‘Port Mapping’. What port mapping does is when it detects an incoming connection of a kind (for example VNC is a type of connection) and routes it through to the IP address on the local network where that Address is needed, so you’re going to want to route it through to the computer you just set with a static IP.

So, It’s likely that your router has to be setup through your web browser so enter the setup and change the router settings so that it routes the VNC from Port 5900 to the IP address of your server computer, now you see why we needed to set a static IP, so that the IP doesn’t change and mess up all the hard work. I can’t help you with the router configuration as they are all different. Before you quit configuring the router make a note of the WAN address of the router as you will need it for the next step.

Next, it’s time to go to the client computer, start up your VNC viewer and make sure you’re connected to the Internet. Type into the viewer the WAN IP address followed by ‘::5900 or whatever port number you chose, so it should look like xxx.xxx.xxx.xxx::590, the x’s being the IP address. Now connect and you should be up and running. If it works fine, why not try it away from home. The only disadvantage to this method of remote control is that every now and then, your routers WAN IP address changes, which makes this method stop working. I don’t know a definite way around that, but I suggest looking into Dynamic DNS (Domain Name Server). I don’t know much about it but I think I’ll have to learn and do a future blog post about it.