Among the many great boons to having a Mac is that it’s easy to set up remote access to a Mac from a Mac over the web. Apple, of course, provides a ‘push one button and make it work’ option for $99 dollars a year. This is part of their MobileMe package. Most of the tools in that package, however, can be found for free elsewhere. That’s for another day, though. For now now, I’m just going to over how to set up free remote screen sharing.

First things first, everything I’m going to talk about relates to Leopard. I don’t believe this feature is built into previous versions. In Leopard, the first step is to turn on Screen Sharing. This can be found in the System Preferences under Sharing. Make sure Screen Sharing is turned on and then take a look at Computer Settings… My recommendation is to add a password here. This is just a precaution so that random people don’t cause havoc with our computer.  So, pick a good password.

With Screen Sharing enable, Remote screen access is easy. With Finder selected, go to Go and then Connect to Server (Shortcut Command + K). A window will pop up with a box for a Server Address. Type vnc://youripaddresshere and hit Connect. If both computers are on a local network, just use the local IP address. If everything is set up correctly, the other computer’s screen should open. However, we’re trying for a truly remote screen sharing experience and just across the room.

To make this even more useful we’re going to use a free service called No-Ip. They provide free urls that can be redirected to a specific IP.  Sign up for an account there and go to to the Members page. Click Add Host, select a Hostname, make sure DNS Host (A) is selected and then enter the routers IP address. This can be found conveniently at this website http://whatismyipaddress.com/.  Once that information has been entered click Create Host.

Users with routers need to take one more step before true screen sharing glory. The port 5900 needs to be forwarded to the appropriate local computer. Each router manufacture does this differently. So, I’m not going to cover the specifics on how to do this. Try a Google search.

Once that’s done, go back to Connect to Server and enter vnc://new.hostname.com. If everything is set up correctly, the computer’s screen should be accessible from anywhere with Mac and an internet connection.

There’s a couple things to keep in mind, it’s going to be slow. Apple’s remote screen sharing client does a wonderful job but it still has to transfer a lot of data over a mediocre connection. Two, I’d turn on full encryption. This just helps protect people form snooping. This can be found when the Screen Sharing application is actually open. Go to Preferences and then select Encrypt all network data (more secure). Lastly, even with encryption turned on, I’m not sure how secure it actually is. So, make sure to protect and back up any sensitive data.

Here the quick and dirty bullet version:

1. Turn on Screen Sharing
2. Set up the proper firewall access and forward port 5900
3. Set up a url with redirection using No-Ip or similar service
4. Turn on encryption
5. Start Screen Sharing

I’ve found a great many uses for this. I often work on the road with my laptop. This gives me access to my computer at home if I forgot a file or just want more processing power. Often I monitored video renders and from time to time I’ve been known to play pranks on people. It’s just another tool in my box. Having remote screen control of a home computer abroad is always a handy thing to have.