For Apple TV owners with slow broadband connections, the ability to download rentals from the iTunes store is bittersweet. Once your rental of choice has downloaded, you're already asleep on the couch after being bored silly by network television. 

If your Internet connection is too slow to watch movies as they download to your Apple TV, you may want to try downloading the movie before watching. In fact, you may want to begin the download while you’re away from home. With the right preparations, you can login to your Mac remotely and begin the download so it’s ready by the time you get home. Sure Back to My Mac will do this, but if you don't have Leopard and a MobileMe account, you're out of luck. Harnessing the power of VNC, we'll get you ready to control your home Mac with not only your work machine, but your iPhone/iPod touch.

What you need: An administrator account on a Mac with iTunes running Mac OS X 10.4.9 or later; A routable IP address for the Mac (less likely on a home network), or the ability to route traffic on certain ports to a non-routable IP address (more likely); A computer outside of the home network with a VNC client; Internet connections for both computers.

To make it work, you want your Mac to accept incoming Virtual Network Computing (VNC) connections; your home network to route the incoming VNC connections to your Mac; and a VNC client to connect to your Mac from across the Internet.

The main drawback of doing it this way is, when using iTunes to rent video, there’s no way to rent the HD version of the movie. (To do that, you need to use Apple TV.) And, though Apple offers its Remote app for iPhone and iPod touch, which theoretically could control the Apple TV from a different network through a VPN, the app doesn’t talk to the iTunes Store. Hopefully, Apple will extend the features of the Remote app for iPhone/iPod touch to talk to the iTunes Store on the Apple TV. Until then, we'll stick with VNC.

1. Set up Mac OS X’s VNC server 

Click to Embiggen

Screen Sharing is built on VNC, or Virtual Network Computing.

Open System Preferences, and click on the Sharing icon to reveal the Sharing preference pane. Click the checkbox next to Screen Sharing (or, under Mac OS X 10.4, Apple Remote Desktop) to turn it on. Click on the Computer Settings button (or, under Mac OS X 10.4, the Access Privileges button) to reveal its corresponding sheet. Click the checkbox next to “VNC viewers may control screen with password” and select a password, preferably with at least eight characters. Click OK, and authenticate as an administrator.

Choose a secure password, because it’s the only thing you use to login, and thus, the only thing an intruder needs to guess.

Use the Energy Saver preference pane to tell your Mac not to sleep.

2. Route VNC traffic to the Mac 

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Picking a dynamic or private port (between 49152 and 65535) prevents intruders from breaking in over the default port.

Telling your Mac to accept VNC connections doesn’t necessarily mean that you can connect to it from elsewhere. If you are running a firewall upstream from your Mac, you may have to tell it not to filter out the VNC Connections.

If your Mac is using a translated address (that is, sharing the IP address assigned by your Internet service provider through a router using Network Address Translation), you need to tell the router how to detect and route the incoming VNC connections.

To do this with Airport Extreme, launch the Airport Utility. Click the Advanced icon at the top, and then click Port Mapping in the pane below. Click the + button to add an entry for VNC connections.

For public TCP and UDP ports, pick a port between 49152 and 65535, and remember it. (This should thwart attempts by hackers to break in over port 5900, the default for VNC). Under Private IP address, enter the translated IP address of your Mac. Under private TCP and UDP ports, enter 5900. Now incoming traffic on the port you picked will be routed to your Mac on port 5900. Click the update button at the lower right to get your Airport Extreme base station to restart with the new configuration.

These settings should work with most routers on the market. Check your routers manual for directions on port forwarding for VNC.

3. Use a VNC Client to connect to your Mac

 
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The movie studios are pretty picky about only one copy of the rental being in use at a time, so be sure to "move" the rental from your Mac to the AppleTV.  

Write down the IP address that your router uses to talk to the Internet (or, if your Mac has a routable IP address, write that down), and take it to work with you. Some Internet Service Providers don’t let you keep the same address from day to day unless you pay for a static IP address, so check back periodically, just in case.

Mocha VNC Lite running on the iPhone