Screen sharing has been around for a long time, and it’s conveniently built into OS X (as well as numerous other apps, such as Messages and Skype). In this chapter, I look at the two modes of remote screen access—broadcasting (you can view my screen) and sharing (you can both view my screen and control my Mac from another device).
Broadcasting is useful for demonstrating how something works—for example, when teaching a class—or letting you monitor what’s happening on a Mac in another location. Sharing, on the other hand, is great for technical support (the person having problems can let someone else “drive” the Mac in order to fix it) or for using multiple Macs without needing them all on the desk in front of you.
Mac users can broadcast or share their screens with other Macs on the same network, using nothing but OS X itself. You can also let someone using an iOS device or PC see or control your screen, with the addition of third-party software.
Enable Screen Sharing
Go to System Preferences > Sharing.
Select the Screen Sharing checkbox ①.
① Activate screen sharing here.
You can now view and control your own screen from other Macs. If that’s all you need, stop here.
To restrict user access, select Only These Users. Then click the plus button to add users.
Optional: You can extend control capabilities to more users by clicking Computer Settings:
Select “Anyone may request permission to control screen” to let other Mac users on your local network connect with your explicit permission.
Select “VNC viewers may control screen with password” (and enter a password) to let VNC clients—including certain iOS apps—control your screen.
View or Control from Another Mac
On another Mac on your local network, look for the shared Mac’s name in the Finder sidebar under Shared. Then:
Select the shared Mac.
Click Share Screen.
If prompted, authenticate with your Apple ID (if using the same iCloud account on both Macs) or your shared Mac’s user account.
The Screen Sharing app is in Control mode by default. To view only, choose View > Switch to Observe Mode.
View or Control from iOS
Because OS X screen sharing is based on the popular VNC protocol, any VNC client, on any platform, can connect to your Mac. Conventional VNC clients require that you have a VNC password entered (see the second bullet under Step 4 of Enable Screen Sharing, earlier in this chapter). But most iOS screen sharing apps directly support OS X’s special flavor of screen sharing, which lets you connect to a specified user account (and doesn’t require an additional VNC password).
Some screen sharing clients for iOS rely on a Mac app that simplifies finding and logging in to your Macs; these may supplement or replace OS X screen sharing. Others go a step further, replacing or rearranging elements of the OS X interface to make them more touch-friendly.
button to add users.