Mac OS X Secrets

Macs have always been great networking computers–both the software and the hardware are a breeze to get up and running. But Mac OS X has brought some significant changes to Mac connectivity. In fact, the new operating system is so different that you may be afraid of losing the effortless network access you enjoyed with Mac OS 9. But you needn’t fear–the news is good.

Only the Names Have Changed

If you can set up a Mac OS 9 network, you’ll feel right at home with OS X. And it gets better: OS X also allows you to connect your Mac in ways you couldn’t before, in a Mac-only network or in a cross-platform network. We’ll show you how to set up Mac OS X networking software, introduce some new features, and get you up-to-speed on keeping your data safe in an increasingly interconnected world.

Get the Network Going

Before you can share files or print from a Mac OS X machine, you’ll need to set up your networking software. Fortunately, you have two factors going for you: TCP/IP is configured already if you used the Setup Assistant when you installed Mac OS X, and OS X’s network settings look and behave much like OS 9’s.

The basis of networking in Mac OS X is TCP/IP, the network protocol that runs the Internet. TCP/IP lets your system communicate with Macs and other machines. The stalwart AppleTalk is still around, but you use it only to print to an AppleTalk printer or to share files with a Mac running pre-OS 9 system software.

TCP/IP configuration is part of the Mac OS X setup, so you should be almost ready to join a network. To check out your TCP/IP status and complete the remainder of your network setup, open System Preferences and click on Network. First verify that the topmost Configure pull-down menu shows a network connection (AirPort or Built-in Ethernet, for example) that matches the way you connect to your local network. Now click on the TCP/IP tab to verify that your IP address and other settings are correct for connecting to your local network. If you’ve used TCP/IP in Mac OS 9, these options will look familiar.

If you need to print to an AppleTalk printer, or if you anticipate that AppleTalk-only Macs will be used to retrieve files from your computer, enable AppleTalk by clicking on the AppleTalk tab and then selecting the Make AppleTalk Active option.

With TCP/IP and AppleTalk running, you’re ready to go–assuming, of course, that your Mac is physically connected to a network. Since the same TCP/IP settings you use for your network will get you on the Web, you can verify that your network is up and running by launching a Web browser.

Set Up File Sharing

To allow and control access to your computer via a network, you’ll need to set up user accounts. Like accounts created with the Users & Groups feature in older Mac OS versions, a Mac OS X user account provides access to your Mac; the OS X account, however, also creates a folder with a predefined set of access privileges.

Making a Mac’s files accessible over a network is a quick, two-step process in OS X: just add users, and activate file sharing. To create a new user account, open the Users item in System Preferences. Click on the New User button and fill in the fields. To make the new user an administrator, with full access to the Mac, select the Allow User To Administer This Machine option. When you’re done, you’ll see the user’s account and a folder named for that user on your hard drive.

To enable file sharing, open the Sharing item in System Preferences, and then click on the Start button located next to the File Sharing heading.

That’s it. You’ve set up your network for file sharing.

Make the Connection

It’s also quite simple to connect to another Mac OS X machine for file sharing. Choose Connect To Server from the Finder’s Go menu; then choose the target Mac from the list of Macs in your local network.

Because Mac OS X uses TCP/IP for file sharing, you can’t log on to a machine running Mac OS 8 or earlier from an OS X machine. If you need to access such a Mac, install Open Door Networks’ ShareWay IP on them ($79 to $1,799, depending on the number of licenses; www.opendoor.com ). This nifty utility gives these systems the same AppleTalk-over-IP access built into Mac OS 9. You must configure TCP/IP on the older machines to make this arrangement work.

You can, however, log on to a shared Mac OS X machine from a pre-OS 9 Mac via the Chooser or Network Browser. To log on to a Mac OS 9 machine from Mac OS X, enable file sharing via TCP/IP in the File Sharing control panel on the OS 9 machine.

With AppleTalk enabled in Mac OS X, you can print to AppleTalk-connected printers. Go to your Applications folder and then to the Utilities folder, and open the Print Center application. Click on the Add Printer button, choose AppleTalk from the pull-down menu, select the printer you want to use, and click on Add.

Multi-What?

Something else is new in Mac OS X. Multilink multihoming is a boon to anyone who needs to connect to multiple networks at the same time. Say your network has a DSL connection for Internet access and a local network for file sharing and printing. Before OS X, you needed third-party software to keep both connections active. Using multilink multihoming, you simply activate multiple network connections and configure their TCP/IP and AppleTalk settings.

To enable this feature, go to the Network pane of the System Preferences control panel and select Advanced from the top Configure pull-down menu. You can then assign priorities to each network connection by dragging its name up or down the list.

Remote Control

Because Mac OS X is Unix-based, you can also access your Mac remotely via a terminal emulator–using Telnet, remote log-in, rsh, or the OpenSSH (Secure Shell) standard. Remote command-line access allows a remote user to issue Unix commands to control the Mac, run Unix applications, exchange files, and do just about anything else.

Though this is a convenient way for administrators to manage systems remotely or to control a Mac via a PC or Unix machine, providing command-line access is the single biggest security risk of sharing your Mac, especially if you use the vulnerable rlogin scheme. For one thing, anyone with a Telnet application and access to your Mac’s account information can log in and take control of your machine. The rlogin command is a favorite entry route for hackers because rlogin does not encrypt data transferred over a network. SSH is much more secure; it encrypts every bit of information you transfer.

If you need to give your Mac remote command-line access, first make sure you’re using the most current version of Mac OS. At press time, Mac OS X 10.0.4 (available as a download from the Apple Web site) was the current version, and it included an update to SSH. Beginning with Mac OS X 10.0.1, Apple changed the default remote log-in application, replacing rlogin with OpenSSH (which encrypts network data, guarding against interception as it traverses the network). Not updating Mac OS could put your Mac at risk.

To access your Mac using SSH, users need a client such as MacSSH or OpenSSH, both of which are available free from many Internet sites, including Macdownload.com.

Cross-Platform Equity

Networking in Mac OS X is a lot like the new operating system itself: things look different, but much of what you’re accustomed to is still there. Even better, this Unix-based OS gives you a new level of network connectivity–making it possible for your Mac to function as an equal in cross-platform networks, and providing the same level of access available to Unix and PC users.

SHELLY BRISBIN is a freelance writer based in Austin, Texas. She is a coauthor of Mac OS X for Dummies (Hungry Minds, 2001).