One of your Mac’s least talked-about OS X features is Back to My Mac. First introduced with Mac OS X Leopard (10.5), Back to My Mac allows two computers to talk to each other over a secure connection. In doing so, you’re able to transfer files and folders between each computer, and also screen share.
What It Is
Back to My Mac uses wide-area Bonjour to discover services across the Internet. Since 2011, the service has been a part of iCloud, Apple’s cloud storage and computing service. Before this, Back to My Mac was part of MobileMe, which was discontinued by Apple in the same year.
To utilize Back to My Mac, you’ll need two or more Mac computers using the same iCloud account. Also required is an AirPort base station or other Internet router that supports UPnP or NAT-PMP (most modern routers will have UPnP enabled by default). The list of devices offering this support includes current-generation AirPort Extreme, AirPort Express, or AirPort Time Capsule devices. An Apple support document specifies additional requirements.
Back to My Mac is only necessary when two or more Mac computers are on a separate network. For example, you might want to use Back to My Mac to communicate with your work computer. In a home environment, the same tasks are performed using AirDrop.
Setting It Up
To use Back to My Mac, the following tasks need to be performed on each computer.
Select System Preferences from the Apple menu at the top right of your device. From there, select iCloud. Be sure you’re already logged into your iCloud account. If you are not, do so. From here, select Back to My Mac. Additional steps may be necessary, depending on your computer setup. These steps are highlighted under the Details button from this location.
One of the likely additional steps that must be performed is turning on NAP Port Mapping (NAT-PMP) or Universal Plug and Play (UPnP). You can do this by heading to your router’s configuration panel, which is usually printed on the underside of your network equipment.
Using AirPort Utility
As an example, we’ll turn on NAT-PMP for an AirPort Time Capsule. If you don’t have an Apple router, you can find specific instructions for your network hardware by searching for “enable upnp” followed by your router make and model.
Open AirPort Utility, located in the Utilities folder in the Applications folder. Next, select the base station to set up, then click Edit. Enter the password if necessary. Click Network and then choose DHCP and NAT from the Router Mode pop-up menu. You’ll need to make sure to select “Enable NAP Port Mapping Protocol,” located under the Network Options button on this same screen. You must also select “Enable default host” and enter the IP address of the host.
Hit Update to complete this process. Turning on NAT-PMP allows clients outside of your private network to contact your computer.
Sharing Your Data
You must perform one additional step before using Back to My Mac. On both computers, go into System Preferences under Sharing. Make sure to check the boxes next to “Screen Sharing” and “File Sharing.”
Next to “Allow access for,” select all users or only listed users. If you permit only certain users to have access to the screen, click Add or Delete to edit the list.
What You Can Do
Once you have activated Back to My Mac, you can perform two main tasks: transfer files and folders between each computer, and share the screen.
All About the Files
The easiest way to access files on another computer is by using the Finder menu bar option Go > Network. From this screen, double-click on your remote computer. Here, you’ll need to select Connect As then enter your security credentials. This is a one-time process; log in once and it should be automatic during subsequent attempts.
You’ll now see shared resources on the remote computer. You can edit and transfer files and folders between each computer just as you would with local data.
Sharing the Screen
Want to control the remote computer? Go into the Finder menu under Go > Network. From here, double-click on your remote computer. Instead of selecting “Connect As”, click Share screen. You should now see the desktop from the remote computer. You’re able to control it just as you would locally.
One of the most valuable tools when sharing a screen is the use of the Clipboard. Without this, you cannot transfer files between computers using screen sharing. Sharing via the Clipboard is turned on by default.
With the Clipboard, you can perform the following tasks, among others:
- Copy text and images from documents on one Mac and paste them in a location on the other computer.
- Select and drag text and images from one Mac and move to the other.
- Copy a link from your web browser and paste it into a web browser on the other Mac.
Back to My Mac Alternatives
One of the biggest drawbacks of Back to My Mac is its setup procedure, which can be tricky. Luckily there are a number of alternatives that will get the job done.
Screens [No Longer Available] is available for Mac and iOS and uses industry-standard technology for remote access (VNC). It’s also very easy to setup and doesn’t require changes to be made to your router. One major drawback, however, is that some corporate policies prohibit Screens from working remotely.
LogMeIn is another popular service. However, it will cost you at least $149 per year for the individual package. For this, you’ll receive remote access, unlimited users, remote printing, and 1TB of file storage. LogMeIn is available on multiple platforms including OS X, iOS, Windows, and Android.
A Final Note
Back to My Mac is an excellent tool. However, depending on your network on both sides, this setup could prove troubling for some users. The best advice is to contact Apple when you have questions. Perhaps most importantly, make sure you have the right hardware before getting started. Some equipment, unfortunately, is too old to get the job done.
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