The Network Preference Pane

Although at first it is easiest to use tools like the Internet Connect application and the Setup Assistant, as your OS X and networking prowess increase, you’ll want to begin to poke around in the Network pane of System Preferences. Doing so provides you with more advanced troubleshooting and more accurate information than the simpler methods, and gives you full manual customization and control over your Mac’s network related behavior. After setting up or connecting to your network, it’s possible that you’ll want to change or add some settings here. Because Mac OS X does do a phenomenal job of automatically handling and sensing network connections, it’s also possible that you won’t need to make any changes at all. Access the Network Preference Pane by opening the System Preferences and clicking on the Network icon.

Understanding ports and locations

Max OS X handles your network connections through a kind of hierarchy. The first stage is your computer’s location. Setting up a location implies that you will really be connecting from different physical locations, but it can be simply creating a specific preference set for a specific connection type that you have. You don’t have to have a portable machine to set up locations. For example, let’s say your cable connection also gives you a free dial-up connection. You can set up a separate dial-up location for use if your cable service is ever out. The next stage is the network ports. Under each location, you can configure multiple ports for connections. A port is a way you connect to a network, like your Ethernet port, or your AirPort card. The default is to have different ports active on a single location, thereby

allowing you to use more than one connection per location. The final stage we’ll call priority. Within an individual location, OS X lets you specify the priority in which ports are used. For example, it is possible to have your modem, your AirPort, and your Ethernet port all configured for one location. But, if you’ve got a good AirPort signal, you wouldn’t want your Mac to start dialing up! To avoid this, OS X lets you choose which port to use first. If you have Ethernet set for first priority, after the Mac senses a good Ethernet signal, it will still take IP addresses from, say, an AirPort connection, but it won’t connect to the Internet with that IP unless the top-priority one, the Ethernet, drops off. Then OS X will fall over to the other connection, more than likely without you even noticing. Because your Mac can actually have multiple IP addresses at the same time (from different ports), it might seem difficult to determine how, indeed, you are actually connected. A bit later we discuss the first thing that you see when you open the Network preference pane, the Network Status screen, which helps you determine just how you are connected. You can also change locations from this initial screen, by selecting different ones from the Location menu. You can edit and create new ones from this menu as well. Notice that the default location of a new Mac is always the Automatic setting, a preconfigured hierarchy of ports to make automatic sensing of a connection as effective as possible. Port-order/hierarchy and locations are discussed later in this Chapter.

Tip

You can have OS X assist you in configuring network settings. Clicking on the Assist Me button brings up a specialized version of the Mac OS Setup Assistant for aiding in the setup of a network. It is similar to the Setup Assistant covered in Chapter 6, but more in tune with the Network preference pane.

Network status display

Open the System Preferences application by choosing it in the Apple menu. The System Preferences application is located in the Applications folder. It is also in the Dock, if you haven’t dragged it out of there. After System Preferences is open, choose the Network pane by clicking on its icon. The first thing you see is called the Network Status area. (See Figure 15-1.) This is an overview of what’s going on, network-connection-wise, in your Mac’s world. You’ll notice two different pull-down menus. One is for choosing your location (we get to that later) and the other is entitled Show. What’s being shown in the network status screen is a list of all your active network ports and their status as related to Internet connectivity.

Figure 15-1: The Network Status display provides a quick display of your network connectivity.

When looking at the Network Status screen, you see three columns, one with an iChat-style colored status indicator dot, one with the name of the network port, and one with a brief summary of how the port is connected. A green dot means that the port is active, that is, you’ve got an IP address, and you are connected to the Internet. Next to the port name (for example, AirPort), OS X gives you a summary of exactly how you are connected. In Figure 15-1, the Mac in question tells you that it’s connected through a Base Station called Warri’s Wireless, and that it’s getting a DHCP address from it. A red dot indicates that the port is inactive. For example, a red dot next to an Ethernet port (Built-In Ethernet) indicates that the cable is not physically plugged in, and your Mac tells you this in the summary area. A red dot next to a modem port indicates that you are not dialed up. A red light next to an AirPort port indicates that there is no wireless signal. An orange dot is an in-between state. In Figure 15-1, the Ethernet DHCP port has an orange dot, and OS X tells you exactly why this is so: The Ethernet cable is plugged in, but the Mac does not have an IP address. Further troubleshooting reveals that the TCP/IP settings were incorrectly set for a manual address.

The order in which the ports appear in the list are important, because they designate in which order your Mac prefers a connection. In Figure 15-1, AirPort is first in the list, and thus the Mac connects over AirPort if a signal that yields an IP address is present. If that is not the case, then the Mac defaults to the next available connection, and so forth down the list. In this way, it is possible to have many different IP addresses at the same time. You could be connected to an AirPort Base Station and have a valid IP address from it, have an Ethernet cable plugged in and have a valid IP from that network, and be dialed up with your internal modem and have an IP address from that connection as well. Each port would show up in the Network Status as having a valid IP address, and thus display a green light in the left column. Although you can have multiple IPs, you can only be connected with one at a time, and again, the Network Status will tell you which port you are actually connected to the Internet with, even though there are multiple ports with IP addresses. In Figure 15-2, both Ethernet and AirPort have valid IP addresses, but because the AirPort connection is first in the list, your Mac tells you that it is actually connected to the Internet with AirPort. If for some reason the AirPort signal fades out, the Ethernet connection takes over.

Figure 15-2: Let the colored dots be your guide. The Network Status display pictured here indicates how you are connected; in this case, both AirPort and Ethernet are being given IP addresses, and AirPort takes priority as it is first in the list.

Configuring the port settings

Now that you’re aware of your network status, you can configure your ports, your connection methods. It might be that after viewing the Network Status, you’ve determined that your Mac is set up and accessing the Internet with reckless abandon. For AirPort and Ethernet, the default connection types are DHCP. Therefore, all you should have to do is plug the cable in or select the AirPort network, and if your network is set up to do so, your Mac will automatically take an address, plug and play, no configuration necessary. Whether this is the case, you should become familiar with all the wonderful things that Network preferences has to offer. The following section covers configuring AirPort, Ethernet, Modem, Bluetooth, and Infrared ports.

Unlocking Network preferences settings

Before you can change any settings, you may need to unlock the Network preference pane. If you are not an administrator of the machine, you’ll need to get an admin name and password before you can make changes.

Note

After changing network settings, click the Apply Now button at the bottom of Network preferences to retain them. If you forget to click Apply Now, Mac OS X asks you whether you want to save your changes as needed.

Common setting panes

It is important to recognize that there are certain settings that are available from more than one port. For example, AppleTalk settings are available under both the Ethernet and AirPort settings. Proxies and TCP/IP are also available under multiple ports, and moreover, can be configured individually per port. This multiple-availability is due to the fact that different connection methods still call upon some similar configurations. Because of this arrangement, we first look at the nonport-specific panel settings, and then move on to configuring the individual ports. You can access the network port settings either by clicking on one from the Network Status list and clicking the Configure button, or by scrolling to the one you wish to choose in the Show menu.

TCP/IP

The TCP/IP configuration is available under every port — AirPort, Ethernet, Modem, and USB Bluetooth Modem Adaptor, because your TCP/IP settings are the very numbers by which you are granted Internet access, no matter how you connect. Typical Ethernet TCP/IP settings are shown in Figure 15-3.

Figure 15-3: Every port has TCP/IP settings. These belong to an Ethernet port.

The connection choices in the TCP/IP pane differ based on the port you have chosen, but, in order to connect, your Mac always needs certain information, whether provided to it or manually set. An IP address, subnet mask, router address, and DNS servers are the minimum settings you’ll need. When using Ethernet and AirPort ports, simply enter the relevant information in the appropriate fields or choose a dynamic connection method. When using a modem, PPP is the usual configure option. In the following list, you find the options that are present in the TCP/IP configuration screen.

• Configure: The method for obtaining some of the other TCP/IP settings for the network connection, such as Manually, Using PPP, Using DHCP, Using DHCP with a fixed IP address, or Using BOOTP.

• DHCP client ID: May be required by your Internet provider to authorize access to your account, especially if you have a cable modem. This setting is present only when the Configure method includes DHCP.

• IP Address: The numerical address for the network connection. This address is a set of four numbers separated by periods, such as 17.254.0.91. This setting is provided automatically by some Configure methods.

• Subnet Mask: Works in tandem with the IP address.

• Router: The IP address of a machine that connects your local network to other networks or the Internet. This setting can be changed only when the Configure method is Manually. Leave this setting blank if your network has no router or gateway.

• Domain Name Servers: One or more IP addresses of computers that translate alphabetic addresses, such as www.apple.com to IP addresses. Put each address on a separate line. This setting is provided automatically by some Configure methods. Domain Name Servers is usually abbreviated DNS.

• Search Domains: One or more domain names, such as nps.gov or berkeley.edu that Mac OS X uses to resolve a partial Internet or network address. For example, if Search Domains contains apple.com, then Mac OS X resolves the partial Internet address www as www.apple.com, livepage becomes livepage.apple.com, store becomes store.apple.com, developer becomes developer.apple.com, and so forth.

AppleTalk

AppleTalk is available under the AirPort and Ethernet connection methods. If you need to use AppleTalk (you might have a network printer or a file server that requires it), you can enable it by checking its box in the AppleTalk pane, as shown in Figure 15-4.

Figure 15-4: Activate AppleTalk with a single click.

If your computer is connected to a network that’s divided into multiple AppleTalk zones, the AppleTalk tab of Network preferences also specifies the zone in which your computer resides. If your computer is connected to a network with only one zone, you won’t have any zones from which to choose.

You should leave the Configure setting at Automatically unless you are an AppleTalk expert. If you are an expert, you know how to set the AppleTalk Node ID and Network ID, which are the settings that appear when you change the Configure setting to Manually.

Proxies

The Proxies pane looks the same from every port. If your computer connects to a local network that is protected from the Internet by a firewall, you may need to configure a port’s Proxies settings. Here, you can specify the proxy servers, which some firewalls use as buffers between a local network and the Internet for privacy, security, and speed. Figure 15-5 shows the Proxies pane.

Figure 15-5: Bypass proxy restrictions in the Proxies pane.

If your Internet connectivity is fine, and you can access everything you need to, then you don’t need to worry about proxies. A network that does have proxy servers almost certainly has a network administrator who can tell you how to configure the Proxies settings. On the left side, you select the proxy server to configure. Check the box if you need to use it. On the right side is a space to type in the Proxy server address; the colon separates the port number that the proxy is set for. Some proxy servers need a password, which can be set by clicking the relevant button. Towards the bottom of the pane you can type in hosts and domains whose proxy settings you want to bypass, for example, if you are on the same network that your email server is on, you might not want to go through the proxy server to access your own local network.

The Proxies pane also lets you choose whether or not to use Passive FTP Mode. When you start an FTP connection, the connection is initiated over the FTP port (20 or 21). In Passive mode, instead of monopolizing the port for the length of your file transfer, the file transfer is done over a different, unused port, which frees up the FTP port for more connections. However, if an FTP site has a firewall in place, Passive FTP usually won’t work, because the unused port intended for the file transfer is usually blocked by said firewall. If you are unable to make a successful FTP connection, turn off Passive FTP mode and try again.

Configuring AirPort

Click the Configure button from the Network Status screen after clicking on AirPort in the list, or use the Show menu to choose it. Under the AirPort section are four panels. Figure 15-6 shows the AirPort configuration screen.

Figure 15-6: Take charge of your AirPort settings here.

AirPort

This pane shows your AirPort card’s hardware address, also called a MAC address. In certain situations, such as a secure wireless network that recognizes computers by their hardware address, you’ll need to know how to find yours. In this pane, you can specify the behavior of your AirPort connection, that is, which network to join by default. Leaving the setting at Automatic will cause your Mac to try to connect to the nearest network it can find. Choose a specific network by pulling the menu down and changing it to join a specific network. Enter a password if necessary. If you’ve got a bunch of locations, or switch networks frequently, setting a specific default connection is a good idea.

At the bottom of the window are two checkboxes. Check the first one if you want your Mac to be able to create its own network, such as a computer-to-computer network. Check the second one if you want to display the AirPort status icon in the menu bar and it is not there. Click Apply Now to save your changes.

TCP/IP

This is the place. Time to type in or select your Internet configuration settings. These terms should all be familiar, as we discuss them in the beginning of this Chapter. Choose the appropriate information and type it all in, or make your selections for receiving a dynamic address. If you are having trouble getting a DHCP address, try clicking the Renew DHCP Lease button. This requests a new lease on the address that you have signed out, or if you have no address, a new one altogether. You also have the option to configure IPv6 (as opposed to IPv4), which is a new form of IP addressing that allows for a greater number of total addresses. As of now, it’s pretty rare, and you may have to have a network admin tell you how to configure it, if necessary. Click on the button to turn it from automatic, to manual, or to turn it off.

AppleTalk

Click the AppleTalk box to make AppleTalk active. As it seems certain that it is slowly being phased out, you might not need to use it; in fact, the default is that it is turned off.

Proxies

Configure your AirPort connection to use proxy servers in the Proxies pane. Click the Apply Now button to save changes.

Tip

You can move most menu bar icons by pressing the Command key and dragging the icon. Drag the icon left or right to change its position relative to other icons on the right side of the menu bar. Drag the icon off the menu bar to make it vanish in a puff of smoke.

Configuring Ethernet settings

If you need to configure your Ethernet port, click on Built-In Ethernet from the Status menu, or scroll to it in the Show menu. The Ethernet option, within the Ethernet configuration screen, is displayed as shown in Figure 15-7.

Figure 15-7: Take charge of your Ethernet-specific settings here.

TCP/IP

Same deal here as with AirPort. Configure as necessary, whether it be for a manual IP address, or a dynamic one. Hit the appropriate button to renew your DHCP lease if you need to. If you need to use IPv6, do so.

PPPoE

If your computer connects to the Internet via DSL, your Internet provider probably requires that you use PPPoE to start each Internet session. You can enter your account name, password, and other information by clicking the PPPoE pane. If the Connect Using PPPoE option is selected, Network preferences displays a PPPoE Options button, and clicking this button displays a dialog in which you can set options that affect the PPPoE session. Figure 15-8 shows the additional settings in the PPPoE Options dialog.

Figure 15-8: Take charge of your PPPoE options here.

The settings in the PPPoE Options dialog have the following effects:

• Connect automatically when needed: Starts a PPPoE session when an application, for example Safari or iChat, attempts to access the Internet.

• Prompt every x minutes to maintain connection: A dialog appears periodically asking if you want to stay connected, and ends the PPPoE session if no one responds to the dialog.

• Disconnect if idle for x minutes: Automatically stops the PPPoE session if no Internet activity occurs on the PPPoE connection during the specified time interval. Because most connections are unlimited (they don’t charge you per minute or hour), it’s good to make the specified time interval fairly sizeable, or to not use this option at all.

• Disconnect when user logs out: Automatically stops the PPPoE session when you log out of Mac OS X, so the next person to log in can’t inherit your PPPoE session.

• Send PPP echo packets: This option makes Mac OS X periodically ask your Internet provider’s computer to respond and ends the PPPoE session if your Internet provider’s computer stops responding. If your Internet provider doesn’t support PPP echoing, then turning on this option may cause your PPPoE sessions to end prematurely.

• Use verbose logging: Creates a detailed log for troubleshooting. A detailed log uses more disk space.

You can show or hide the PPPoE status icon in the menu bar by selecting or deselecting the option labeled Show PPPoE status in menu bar. You see the effect of changing this setting immediately. If the PPPoE status icon is hidden and you click this checkbox, the PPPoE status icon appears to the left of other icons on the right side of the menu bar. You can use the PPPoE icon to connect to the Internet, disconnect from the Internet, and monitor the connection status, as described in Chapter 6.

AppleTalk

Same as usual. Check the box if you need it. Leave it alone if you don’t. Interestingly, AppleTalk cannot be enabled on an Ethernet port if PPPoE is active. Creating new ports is covered later in the Chapter.

Proxies

If you need it, you’ll know it. Configure as necessary.

Ethernet

A special Ethernet section (within the Ethernet section) lurks. The first thing that is displayed is your Mac’s hardware Ethernet address, or MAC address. Most commonly, Ethernet will be set to Configure: Automatically and doesn’t need to be changed. If you are troubleshooting a network issue, or tinkering around, you might want to switch from automatic to manual. Doing so gives you the ability to select the speed of your Ethernet port manually (you might want to set it slower, at 10BaseT, to test stability on a problem-prone network) and to control the size of the packets that your Mac sends over the Network.

Click Apply Now to save changes made to your Ethernet Settings.

Configuring Modem settings

Select the Internal Modem port to configure settings for dial-up Internet Access. Figure 15-9 shows the Modem configuration area.

Figure 15-9: Take charge of your Internal Modem settings here.

PPP (Point to Point Protocol)

Click the PPP pane in Network preferences to configure a modem connection to the Internet or a remote network. You can enter the name and password required for connecting to your Internet account, the telephone number that your computer must call to get connected, an alternate telephone number to call if the main number is busy, and the name of the service provider. To display a dialog of additional options that affect a PPP session, click the PPP Options button. Figure 15-10 shows the additional settings in the PPP Options dialog.

Figure 15-10: The wealth of PPP connection options.

The PPP options have the following effects:

• Connect automatically when needed: Starts a PPP session when an application, for example Mail or Sherlock, attempts to access the Internet.

• Prompt every x minutes to maintain connection: Causes a dialog to appear periodically, asking if you want to stay connected, and ends the PPP session if no one responds to the dialog.

• Disconnect if idle for x minutes: Automatically stops the PPP session if no Internet activity occurs on the PPP connection during the specified time interval.

• Disconnect when user logs out: Automatically stops the PPP session when you log out of Mac OS X, so the next person to log in can’t inherit your PPP session.

• Redial if busy: Specifies how to redial the service provider’s telephone number if it is busy.

• Send PPP echo packets: Makes Mac OS X periodically ask your Internet provider’s computer to respond and ends the PPP session if your Internet provider’s computer stops responding. If your Internet provider doesn’t support PPP echoing, then turning on this option may cause your PPP sessions to end prematurely.

• Use TCP header compression: Makes Mac OS X try to compress TCP header information for efficiency. Leave this option turned on because the service provider can refuse header compression without causing a problem.

• Connect using a terminal window (command line): Causes a terminal window to appear while you’re connecting so that you can type commands and enter requested information for your service provider.

• Use verbose logging: Creates a detailed connection log for troubleshooting purposes. A detailed log uses more disk space.

TCP/IP

For a dial-up connection, the TCP options are quite different. Most commonly, TCP/IP is set to use PPP to dial up. If you are using an AOL connection, choose the AOL option. In rare cases your ISP will need you to configure a dial-up connection manually, and the option to do so is present.

Proxies

Configure as you would for either AirPort or Ethernet. Because most dial-up connections are commonly away from offices and firewalls, configuring Proxies while using a dial-up connection is rare, but sometimes necessary.

Modem

Click the Modem pane to identify the type of modem you have and to set certain dialing options. Your Mac should default to the correct modem type, but you can find out just what type of modem you have by viewing the modem area of the Apple System Profiler, as shown in Figure 15-11. (Find Apple System Profiler in the Utilities folder, or by going to the Apple Menu and choosing “About This Mac” and clicking on the “More Info” button.) The V number that comes after the modem type represents the speed and features supported by the modem. Newest modems use the V.92 protocol, which supports 56K connection speeds and can use call-waiting to receive voice calls even if you are dialed up to the Internet. The V.90 script supports the 56K speeds, but not call-waiting. Lower numbers are for lower speeds. If you’re not sure which to use, try the higher one first and work your way down.

Figure 15-11: Use the System Profiler if you are unsure of your modem type.

The first checkbox is for enabling error correction and compression. If you wish to use speeds above 33.6K, you’ll need to have this box checked. If you are having trouble maintaining a faster dial-up speed, unchecking this box can lead to more stability. The second checkbox tells the computer to wait for the dial tone before dialing. If your phone doesn’t always give a clean dial tone (such as a voicemail system whose dial tone changes to alert you of new messages) you’ll want to uncheck this box.

If your phone is a pulse-dialing model, you’ll need to select that option. Almost all phones are tone, so you should probably not select this option.

If you want the modem sound off, you can select the sound off option. Leaving the sound on is usually a good idea, as an aural indicator that your Mac is dialing-up properly.

If you have call-waiting, you can set your Mac to warn you when an incoming call is received when you are dialed up. You can choose to have an alert sound play, and to be warned before being disconnected.

If you change countries, you should alter the modem settings to reflect your new location.

You can show or hide the Modem status icon in the menu bar by selecting or deselecting the option labeled Show Modem status in menu bar. You see the effect of changing this setting immediately. If the Modem status icon is hidden and you select this option, the Modem status icon appears to the left of other icons on the right side of the menu bar. You can use the Modem icon to connect to the Internet, disconnect from the Internet, and monitor the connection status, as described in Chapter 6.

If you have a slightly older Mac, you might have an infrared port. All the PowerBook G3s have them, as well as the earlier PowerBook G4s, and the original Bondi Blue iMac. You can use the infrared, or IR, port to connect to the Internet through an IR-equipped Palm device or cell phone. Configuration is almost identical to both the regular internal modem and a Bluetooth modem (which we cover in the next section). IR is much slower and requires a direct line of sight between the devices.

Configuring the USB Bluetooth modem adaptor

One of the niftier features of OS X is the ability to use a Bluetooth-enabled mobile phone to dial your Mac up to the Internet. This is especially cool (although a bit slow) if you have a PowerBook and are without Internet, whether you’re in a cab riding through Central Park, or are actually in Central Park. You’ll need to set up your phone using the Bluetooth Setup Assistant first (Chapter 6). After you are dialed up through your cell phone, you can even go as far as to set your computer to share its connection over AirPort (see Chapter 10) and broadcast an Internet signal to other computers.

The Bluetooth modem is configured identically as the internal modem would be with respect to the TCP/IP, PPP, and Proxies panels. The unique panel is the Bluetooth Modem panel. Instead of choosing a modem script to reflect your Mac’s internal modem, the modem script needs to reflect your cellular phone model. If it’s not present, you can go to www.apple.com/ bluetooth for information and downloads. You are also given the option to show the Bluetooth status in the menu bar. Otherwise, you initiate a connection just like you would a regular dial-up. You can click Dial Now right from the PPP panel, or use the Internet Connect application, or use the modem menu bar icon. See Figure 15-12 for the Bluetooth Modem setup.

Figure 15-12: The unique settings for your Bluetooth modem adaptor.

Tip

A port exists, called 6 to 4, that does not show up by default in OS X 10.3. In order to create it, you have to view the port list and create a new one, under the Network Port Configurations area. A 6 to 4 is used when you, on an IPv6 network, need to access another IPv6 network, over the Internet, which is still IPv4 based.

Configuring network ports

Mac OS X lets your computer have more than one network port active at the same time. Therefore, as previously stated, your computer can have concurrently active configurations of AirPort, Ethernet, and modem connections. You can even have multiple configurations of the same port, all of them operating in conjunction.

Multiple port configurations can provide overlapping services. On a PowerBook that you use in different locations, Ethernet can provide fast Internet access from the local network at your desk. AirPort can provide wireless Internet access when you’re in meetings. A modem can provide Internet access when you’re at home. On this PowerBook, the Ethernet, AirPort, and modem configurations are active all the time, and Mac OS X is able to determine which configuration to use for Internet access at any given time and/or location.

Somehow, Mac OS X has to determine which of the available port configurations to use when you start to check your email, browse the Web, print, or use some other network service. Mac OS X has a simple method of prioritizing port configurations. It goes down a list of available port configurations, trying each in turn, and uses the first one that works. By default, Mac OS X tries port configurations in the following order: internal modem, built-in Ethernet, and AirPort. (This is the Automatic location.)

You can change settings in Network preferences that affect which port configuration Mac OS X uses. You can do the following:

• Change the priority of port configurations.

• Turn each port configuration on or off.

• Create additional port configurations that use the same ports as existing configurations.

• Rename port configurations.

• Delete port configurations.

Displaying network port settings

To display the settings that affect which port configuration Mac OS X uses, choose Network Port Configurations from the Show pop-up menu in Network preferences. If the Location pop-up menu lists more than one network location, make sure that it is set to the one whose port configurations you want to see. Figure 15-13 shows an example of Network Port Configurations settings.

Figure 15-13: Change the Network Port Configurations settings in Network preferences to affect which port configuration Mac OS X uses.

The Network Port Configurations settings of Network preferences include a list of all port configurations. This list shows the order in which Mac OS X tries the port configurations. You can give a port configuration a higher priority by dragging it higher on the list. You can give a port configuration a lower priority by dragging it lower on the list.

Tip

Drag the port configuration you use most often to the top of the Port Configurations list. Now Mac OS X won’t waste time checking less-used port configurations.

You can turn a port configuration on or off by selecting or clearing the checkbox next to its name in the Port Configurations list. When a port configuration is turned off, Mac OS X doesn’t try to use it.

Tip

Turn off port configurations that you never use so that Mac OS X won’t waste time checking them.

Working with port configurations

You can create additional port configurations by making new ones or duplicating existing ones.

To make a new port configuration

Click the New button in the Network Port Configurations settings of Network preferences. In the dialog that appears, enter a name for the new configuration and choose the new configuration’s port from the pop-up menu.

To duplicate a port configuration

Select a port configuration in the Network Port Configurations settings of Network preferences and then click the Duplicate button. As shown in Figure 15-4 a dialog appears in which you can edit the name that Mac OS X proposes for the duplicate port configuration.

Figure 15-14: Choosing to duplicate a port presents you with the dialog, which gives you the option to name your duplicate.

To rename a port configuration

Double-click on the port name that you wish to edit and type in what you wish to call it. Hitting return selects the next name in the list.

To delete a port configuration

You delete a port configuration by selecting it in the Network Port Configurations settings of Network preferences and then clicking the Delete button. An alert appears asking you to confirm that you really want to delete the port configuration.

When you create a new or duplicate port configuration, Mac OS X puts it at the bottom of the list. You can drag it higher to raise its priority.

Working with network locations

You may find that you need to make regular changes to settings in Network preferences. For example, you may use your computer in locations that need to have different network settings. Every time you change locations, you have to remember what changes to make and then click and type repetitiously to make the changes. You can simplify the process of changing locations by letting Mac OS X do the repetitive part.

You learned how to view the status of the entire network, then how to configure and work with individual ports. This section covers how to create locations of different groups of ports, or a single port. You can create network locations in Network preferences to facilitate making regular changes to network settings. Each network location is simply one specific arrangement of all the various Network preferences settings. When you create a network location, you give it a name. The names of network locations appear in the Apple menu and in the Location pop-up menu at the top of Network preferences. In fact, the network locations appear in these places for all users of your computer; they are system-wide settings. (User accounts don’t have private network locations.)

After you create a network location for a particular arrangement of network settings, you can quickly change to that arrangement by choosing the network location by name from the Apple menu. This method of reconfiguring the Network preferences settings is much quicker and simpler than changing all the individual settings involved in the reconfiguration.

Here are some situations in which you may want to create network locations:

• You use the computer in more than one place, such as at home and at work or school, with different port configurations at each place.

• You connect to different networks from the same port, such as a modem connection to your Internet provider and a modem connection to your network at work or school.

• You set different port priorities to determine which port configuration your computer will use for network services that are available on more than one network port, such as file sharing on Ethernet or AirPort.

You use the Location pop-up menu near the top of Network preferences to create, rename, and delete network locations. You use this same pop-up menu to select a network location that you need to reconfigure. You can also use this pop-up menu to switch network locations, but the Apple menu is usually more convenient.

Creating new network locations

You can create additional network locations by making new ones or by duplicating existing ones. To make a new network location, choose New Location from the location pop-up menu, and enter the name in the dialog box that appears. Click OK to save the name, and click Apply Now to retain the new Location. To duplicate a network location, choose edit from the Location pop-up menu, select the location that you want to duplicate and click the Duplicate button. The duped location now appears in the list with the suffix Copy, and its name highlighted, ready to be changed. Change the name and hit the Done button. Click the Apply Now button to retain the settings.

Switching network locations

We already revealed the easiest way to switch to another network location, which is to use the Apple menu. Specifically, you choose the network location by name from the Location submenu in the Apple menu.

You can also switch the network location by choosing the one you want from the Location pop-up menu in Network preferences, but you must click the Apply Now button at the bottom of Network preferences to make the switch take effect. This allows you to view your different locations without changing your current network settings at the same time.

Reconfiguring network locations

Location settings can be changed at any time, by going into the Network preferences and changing the port settings, or the ports themselves. Network locations can also be renamed, or deleted by using the edit option under the Location pop-up menu.