macOS Sierra: The Missing Manual

Remote Access with SSH

Are you a geek? Take this simple test at home: Do you get excited about macOS’s ability to permit SSH access?

If you answered “What’s SSH?” or “I’m already being quiet,” then the following discussion of Unix remote control may not interest you. To be sure, SSH is not a program with a graphic user interface (icons and menus). You operate it from within a program like Terminal by typing commands. (For details on Terminal, see the free downloadable appendix called “Terminal Crash Course” on this book’s “Missing CD” page at www.missingmanuals.com.)

Up to Speed: The IP Address Mess: Port Forwarding

There are so many ways to connect to your Mac from another computer. You can use SSH, file sharing, screen sharing, and so on. They’re easy to use—when you want to connect across your home or office network.

When you want to connect from across the Internet, though, things get complicated fast.

In that case, you need to know your home Mac’s IP address. (IP stands for Internet Protocol.) An IP address is always made up of four numbers separated by periods, like 192.168.1.104. Every computer on earth that’s directly connected to the Internet has its own unique IP address.

Now, if you have only one Mac, and it’s connected directly to your broadband modem, no big deal. You can find out its IP address by opening System Preferences, clicking Sharing, and turning on File Sharing.

Unfortunately, your Mac at home probably isn’t connected directly to the Internet. If you’re like most ...