You'll connect immediately and see a tips panel showing some control tricks. However, in short, the mouse cursor is represented by a small dot and you "shove" it around — push up on the screen, for example, and wherever the mouse cursor happens to be it will also move up. It can take a bit of getting used to. Tapping on the screen is the equivalent of clicking. Use the pinch-expand gesture to zoom in and out of the desktop.
To make a keyboard appear for typing, tap the keyboard icon on the toolbar at the top of the screen. To disconnect from the remote Mac, tap the X icon on the toolbar.
Using the free VNC Viewer app you can remotely control your Mac's desktop
If you want to connect to a Linux desktop you can install a VNC server package (just check your distro's package archive), and the same VNC Viewer app can be used to connect as described above.
Connect to remote Windows computers via your iPad or iPhone
Microsoft has a surprising number of apps available for iOS and one of them is Microsoft Remote Desktop. This lets you remotely connect to the desktop of Windows computers. You'll find it in the App Store and it's free of charge.
In typical Microsoft fashion not all versions of Windows have Remote Desktop compatibility built-in, and it's limited to the Ultimate, Business and Professional editions of XP, 7 and 8. (Although there are hacks to make it work on other versions — just Google.)
Before using Remote Desktop you'll need to ensure it's activated on the Windows computer you want to access. This can be done by clicking Start and typing Allow Remote Access To Your Computer. Then click the entry that appears in the results, and click Allow Connections Only From Computers Running Remote Desktop with Network Level Authentication (More Secure). Then click OK.
You'll need to activate Remote Desktop on Windows but it's only available on Ultimate, Business and Professional editions of the OS
You'll also need to know the IP address of the Windows computer. Click Start, then type cmd. In the DOS box that appears, type ipconfig and hit Enter. In the output, look for the line that reads IPv4 Address and make a note. Then close the DOS box.
Start the Microsoft Remote Desktop app on your iOS device and click the plus button in the top right, then select Add PC or Server. In the PC Name field, type the IP address you noted earlier. Tap the User Name field, then tap Add User Account. Now type the username and password of the Windows computer you want to access, and tap Save, and then Save in the parent dialog box. Then tap the icon for your new connection. You'll be asked immediately if you want to accept the security certificate. Tap the switch alongside Don't Ask Me Again and then tap Accept.
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