Switching to the Mac: The Missing Manual, Tiger Edition

chapter 9: getting online 251

To turn it on, open the Sharing pane of System Preferences. Click the Firewall tab

(Figure 9-4), and then click Start. That’s all there is to it: You’re protected.

Note: If you’re using Mac OS X’s Internet connection-sharing feature, turn on the firewall only for the first

Mac—the one that’s the gateway to the Internet. Leave the firewall turned off on all the Macs “downstream”

from it.

And if you have some program that’s raising trouble because it can’t get through your firewall (an online

game, for example), head back to the Sharing pane and click Add. In the dialog box that appears, choose

Other from the Port Name menu and fill in the lower fields as instructed in the program’s help files. You’ve

now allowed that program’s traffic to pass unimpeded through your Mac’s firewall.

Switching Locations

If you travel with a laptop, you may wind up connecting to the Internet differently

in each location: Ethernet at the office, dial-up in the hotel room. Or maybe you

Figure 9-5:

The Location feature lets you

switch from one “location” to

another just by choosing its

name—either from the a menu

(top) or from this pop-up menu

in System Preferences (bottom).

The Automatic location just

means “the standard, default

one you originally set up.” (Don’t

be fooled: Despite its name,

Automatic isn’t the only location

that offers multihoming, which is

described later in this ...