Exploring the Mac's sharing features

Advanced sharing options

We now venture into options intended for advanced users. Rather than confuse you with a lot of technical terms and convoluted explanations, I’ll lay out the gist of what the remainder of the sharing options do.

Remote Login: This sharing option allows you or other people to gain remote access to your computer’s files. To do so, they use something called the Secure Shell (or SSH) scheme. This scheme requires that the person attempting to log in know the username for the account you wish to access, the account’s password, and the computer’s IP address. (I discussed IP addresses when I discussed setting up your network.) As with File Sharing, you can choose to allow anyone in who has this information, or you can restrict access to individual users that you specify.

The advantage of remote login is not only that it lets others on your network gain access to your files, but also, through a bit of configuration magic that I won’t go into now, that it lets people on the Internet outside your local network do so. But it has its dangers as well. Some baddies may try to hack into your computer via the SSH port and conduct something called a “brute force attack” (use a program that hurls password after password at your Mac until it finds the correct one). If you’re Joe MacUser and have a solid password (a combination of numbers and characters that don’t spell an actual word) you’re not likely to succumb to such an attack. (Nor, honestly, is a typical user likely to be a target of one.) Still, if you don’t have a need to switch Remote Login on, don’t.

Remote Management: I’ve already discussed the Screen Sharing option. Remote Management is similar though it’s largely intended to be used with Apple Remote Desktop, an application that helps network administrators remotely manage groups of Macs. Again, you must choose who can have access to your Mac. And also again, if you don’t understand or need this capability, leave it off.

Remote Apple Events: Built into the Mac are tools for automating tasks on your computer. Many such tasks are created with and executed by something called AppleScript. When you enable this sharing preference, you’re telling your Mac to accept actions (or "Apple Events") sent from another computer on the network. For example, an Apple Event might tell your Mac to print all the documents within a particular folder on your desktop. As before, you can choose who you grant this power to. And yes, leave it off if you don’t understand or need it.

Internet Sharing: Suppose you’re in a hotel that offers a wired Internet connection rather than Wi-Fi. You can plug your MacBook Pro into this connection to get on the Internet, but what about your Wi-Fi iPad? If only you could somehow share the Mac’s connection...

You can, and Internet Sharing is the way. In our scenario, choose Ethernet from the 'Share your connection from' pop-up menu, and select Wi-Fi in the 'To computers using' list. Or in English, “Hey, my Mac’s connected to the Internet via an ethernet cable. You’re welcome to share that connection with your iPad over Wi-Fi.”

Internet sharing options.

When you switch on Internet Sharing, you’ll be asked if you really want to do this (of course you do). Click Start. The Wi-Fi icon in the menu bar will turn gray and display a white upward-pointing arrow, indicating that it’s sharing its Internet connection. On the device you wish to use to glom onto that connection, open its Wi-Fi settings and choose your Mac as the hotspot.

If you don’t want everyone and her brother sharing this connection, click the Wi-Fi Options button at the bottom of the Sharing window before you enable Internet Sharing. In the sheet that appears, you can name the network, choose a channel (you’re safe leaving it at 11), and select the kind of security that you wish to use ('None' or 'WPA2 Personal'). If you choose to use security, you’ll have to enter and confirm a password for your network.

Bluetooth Sharing: Bluetooth is a short-range networking scheme that lets you do things such as broadcast music from your iPhone to a set of wireless headphones or to a car’s audio system. Wireless mice, trackpads, and keyboards also use Bluetooth to send their signals to your computer.

You can also share files over Bluetooth, a capability that can come in handy if you have a couple of Macs that you can’t network in another way (because there’s no Wi-Fi available, for example). This is how to do it.

First, enable Bluetooth Sharing. Once you've done so, you have some decisions to make. One is to figure out how to handle an item that you receive as a Bluetooth transfer. You can automatically accept and save it, automatically accept and open it, receive a prompt to manually accept or decline it, or never allow such transfers. You then select a folder where you’d like transferred items to appear (Downloads is the destination by default).

Choose your Bluetooth sharing options.

Another user can also browse your computer over Bluetooth. In the next section of the window, you may choose  to allow this browsing automatically or to be presented with a dialog box where you can make such decisions case by case. In the same section of the window, you also select the folder that the connected user can browse. (By default, this is the Public folder within your user folder, but you can select a different one.)

To establish a connection over Bluetooth, each party must have Bluetooth switched on and discoverable. (Both options are located in the Bluetooth system preference.) To make a connection, click on the plus (+) button at the bottom of the Bluetooth window. Bluetooth Setup Assistant will launch, and the names of any discoverable devices will appear in its window. Select the one you wish to connect with, and click Continue.

Bluetooth Setup Assistant will generate a code on the Mac where it’s currently running and will send that code to the device that you wish to connect to. The other device must acknowledge that code. Once it does, the two devices are paired. Quit Bluetooth Setup Assistant, and you’ll find your paired device listed in the Bluetooth system preference.

Bluetooth pairing requires that a code be acknowledged.

To send a file to a paired device, click the Bluetooth menu in the menu bar, locate the name of the paired device, and choose Send File from the device’s submenu. In the window that opens, you can navigate to the item you wish to send. Select the item and click the Send button in the window. An Incoming File Transfer window will appear on the other Mac by default. Click Accept on that Mac, and the system will transfer the file to the folder configured to accept it.

You can browse another device similarly. Click the Bluetooth menu, but this time choose the paired device and select Browse. You can then see the contents of the folder that the other user has granted you access to.

Note that you can’t use Bluetooth to share files between iOS devices. Although the iPod touch, the iPhone, and the iPad have Bluetooth capabilities, they don't support file transfer.

The last thing: AirDrop

If this last operation sounds especially tedious, I have good news for anyone who uses Lion or Mountain Lion with a fairly recent Mac and wishes to quickly transfer items from one Mac to another. That good news is called AirDrop, and it works like this.

With each Mac connected to Wi-Fi, open a Finder window on both computers. Select AirDrop in each window’s sidebar. Any Macs that are running Lion or Mountain Lion on your local network and that have their AirDrop window open will appear as round icons in the window, with their names below. To transfer a file from your Mac to another Mac, simply drag the file on top of the other computer’s icon. You’ll be asked if you’d like to send that file. Click Send, and a notification will appear on the other Mac, inviting you to save and open, to decline, or to save. Click Save and Open or Save, and the item will be transferred to the other Mac and placed in that Mac’s Downloads folder.

AirDrop makes it a cinch to swap files with another person who's running Mountain Lion.

If that Mac can open the file, and you’ve chosen 'Save and Open', it will do so in the appropriate application. If the Mac lacks the necessary application to open the file, but the Mac is aware of which application created it (and that application is available from the Mac App Store), a notification will warn you that you’re missing the application, but that you can get it from the Mac App Store. Tell your Mac to get it, and the Mac App Store application will open and direct you to the application. You can then choose to purchase it.

Not all Macs capable of running Lion support AirDrop (because they lack the proper wireless hardware). However, not all is lost. Mac OS X Hints has a tip that shows you how to enable AirDrop on older Macs that can run Lion. (This is a tip for advanced users so if touching the Terminal frightens you, stay away.)

Next week: Users & Groups

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