Chapter 21

Building (Or Joining) a Network

In This Chapter

Considering the benefits of a network

Choosing between wired and wireless networks

Sharing an Internet connection

Gathering the stuff you need to network

Making the network connection

Using your network

Protecting your iMac with a firewall

In my book, network access ranks right up there with air conditioning and the microwave oven. As with other “I can’t imagine life without them” kinds of technologies, it’s hard to imagine sharing data from your iMac with others around you without a network. Sure, I guess you could still create a sneakernet (the old-fashioned term for running back and forth between computers with a floppy disk), but these days, Apple computers don’t even have floppy drives. (Even with a USB flash drive, a sneakernet is still a hassle.)

Whether you use your network to share an Internet connection, challenge your friends to a nice relaxing game of World War II battlefield action, or stream your MP3 collection to other computers that use iTunes, you’ll wonder how you ever got along without one. In this chapter, I fill you in on all the details you need to know to get your iMac hooked up to a new (or an existing) network.

What, Exactly, Is the Network Advantage?

If you have other family members with computers or if your iMac is in an office with other computers (including those rascally PCs), here’s just a sample of what you can do with a network connection:

• Share an Internet connection. This is the major reason that many families and most small businesses install a network. Everyone can simultaneously use the same digital subscriber line (DSL) or cable Internet connection on every computer on the network, while easily communicating and sharing files with each other at the same time.
• Share a printer. You say your fellow employee — or even worse, your big sister — has a great printer connected to her computer? Luckily, that printer can be shared with anyone across your network.
• Copy and move files of all sizes. Need to get a large iMovie project from one Mac to another? With a network connection, you can accomplish this task in just seconds. Otherwise, you’d have to burn that file to a DVD-R or use a flash drive. A network connection makes copying as simple as dragging the project folder from one Finder window to another.
• Share documents across your network. Talk about a wonderful collaboration tool. For example, you can drop a Microsoft Word document or Keynote presentation file into your Public folder and ask for comments and edits from others in your office.
• Stream music and video. With iTunes, you can share your audio and video media collection on your iMac with other Macs and PCs on your network. Your eyes and ears can’t tell the difference!
• Play multiplayer games. Invite your friends over and tell ’em that you’re hosting a LAN party — that’s the techno-nerd term for a large gathering of game players, connected through the same network, all playing the same multiplayer game. (Suddenly you’ll see firsthand just how devious a human opponent can be.) Each participant needs to buy a copy of the same game, naturally, but the fun you’ll have is worth every cent you spend. Don’t forget the chips!

If your iMac isn’t within shouting distance of an existing network or you don’t plan on buying any additional computers, stop right here — a lone iMac hanging out in your home with no other computers around probably won’t need a network.

If you have just your iMac and an Internet connection and you have no plans to add another computer or a shared printer, a network isn’t necessary.

The Great Debate: Wired versus Wireless

After you decide that you indeed need a network for your home or office, you have another decision to make: Should you install a wired network (running cables between your computers) or a wireless network? Heck, should you throw caution completely to the wind and build a combination network with both wireless and wired hardware?

Your first instinct is probably to choose a wireless network for convenience. After all, this option allows you to eliminate running cables behind furniture (or in the ceiling of your office building). Ah, but I must show you the advantages to a wired network as well. Table 21-1 shows the lowdown to help you make up your mind.

Table 21-1 Network Decision Making

As I call it, here are the advantages of choosing a wired or a wireless network setup:

• Wired: Using a wired network offers two significant perks over a wireless network:
  • Faster speeds: In general, wired networks that are compatible with your iMac are many times faster than the fastest 802.11n or 802.11ac wireless connections.

    The performance of a wireless connection can be compromised by interference (from impeding structures, such as concrete walls; and from household appliances, such as some wireless phones and microwave ovens) and by distance.

  • Better security: A wired network doesn’t broadcast a signal that can be picked up outside your home or office, so it’s more secure.

    Hackers can attack through your Internet connection. Always use a firewall. I subtly emphasize this point in the section “USE YOUR FIREWALL!” later in this chapter.

• Wireless: A wireless connection really has only one advantage, but it’s a big one: convenience (which, in this case, is another word for mobility for all your networked devices).

  Accessing your network anywhere within your home or office — without expensive cables — is so easy. You can also easily connect a wireless printer. And when you’re using an AirPort Express mobile Base Station, even your home stereo can get connected to your MP3 collection on your iMac. Read more about Base Stations later on.

Sharing Internet Access

It’s time to see what’s necessary to share an Internet connection. In this section, I cover two methods of connecting your network to the Internet. (And before you open your wallet, keep in mind that you might be able to use your iMac to share your broadband connection across your network!)

Using your iMac as a sharing device

Figure 21-1 illustrates how you can use your iMac to provide a shared Internet connection across a simple wireless network, using either

• A broadband DSL or cable connection
• A Mavericks-compatible external USB dialup modem

  I recommend sharing a dialup modem Internet connection only if you have no other option. A dialup modem connection really can’t handle the data transfer speeds for more than one computer to access the Internet comfortably at one time. (In plain English, an external USB modem that you add to your iMac isn’t fast enough for both you and your significant other to surf the web at the same time.) Sharing a dialup connection just isn’t practical — and for many folks, even a single computer accessing the Internet over a dialup modem connection is far too slow.

In either configuration, your iMac uses the OS X Mavericks built-in Internet connection sharing feature to get the job done, but your iMac must remain turned on to allow Internet sharing. I show you how to do this in “Network Internet connections,” later in this chapter.

Using a dedicated Internet sharing device

Figure 21-2 illustrates how a broadband connection works if you use a dedicated Internet sharing device (often called an Internet router) to connect to your cable or DSL modem. You have to buy this additional hardware, but your iMac doesn’t have to remain turned on just so that everyone can get on the Internet.

Internet routers usually include either wired or wireless network connections — and many include both.

Setting up an Internet router is usually a pretty simple matter, but the configuration depends on the device manufacturer and usually involves a number of different settings in System Preferences that vary according to the model of router you’re installing. Grab a diet cola, sit down with the router’s manual, and follow the installation instructions you’ll find there. (In some cases, you may need to set up your cable or DSL modem as a bridge between your ISP and your router, which should be covered in your modem and router manuals as well.)

Most Internet routers offer a DHCP (Dynamic Host Configuration Protocol) server, which automatically assigns Internet protocol (IP) addresses, and I strongly recommend that you turn on this feature!

What Do You Need to Connect?

Most normal folks — whom I define as those who have never met a network system administrator, and couldn’t care less — think that connecting to a network probably involves all sorts of arcane chants and a mystical symbol or two. In this section, I provide you with the shopping list that you need to set up a network, or connect to a network that’s already running.

Wireless connections

Today’s iMacs come complete with built-in AirPort Extreme wireless hardware, so if you already have an AirPort Extreme or Express Base Station, you’re set to go. Otherwise, hold on tight while I lead you through the hardware requirements for wireless networking. (Kinda ironic, don’t you think?)

The maximum signal range — and effectiveness — of any wireless network can be impeded by intervening walls or by electrical devices, such as microwave ovens and some wireless phones, all of which can generate interference.

Connecting an iMac to an existing wireless network

Connecting an Intel iMac to an existing wireless network requires no extra hardware because your hardware is already built in. (Whew. That was easy!)

Using a base station to go wireless

If you decide that you want to build your own wireless network, you eschew cables, or you want to add wireless support to your existing wired network, you need a base station. The base station can act as a bridge between computers using wireless and your existing wired network. Such a wireless base station will have either

• A port that can connect to your existing wired network’s switch
• A full built-in switch for wired connectivity (which means you can sell your old wired Ethernet switch to your sister in Tucson)

And, of course, a base station can simply act as a central switch for your wireless network (with no support for a wired network at all).

You can use either a cool Apple Base Station or a boring 802.11n or 802.11ac generic wireless base station; however, the Apple hardware requires less configuration and tweaking. (Sounds like a Mark’s Maxim!)

If you don’t want the hassle of tweaking PC hardware to accommodate your iMac, buy Apple hardware and software.

Apple Base Station models

As listed in Table 21-2, your iMac can work with three different Apple Base Station models for wireless networking:

• AirPort Extreme

  I recommend using AirPort Extreme if your network needs an enhanced antenna, which provides greater range. You can read about connectivity ranges in the upcoming Table 21-2. The Extreme is also a good pick if you need wired connectivity on your network.

• AirPort Express

  I recommend using AirPort Express if you want to

  • Carry your wireless base station with you. Express is much smaller than the other Apple Base Station models. (Think “party on the patio” or a LAN gaming get-together at a friend’s house.)
  • Extend the range of an existing network. Add an Express at the limit of your existing wireless network, and you can benefit from the additional range it provides.
  • Connect your home stereo for wireless music streaming. You can use the AirPlay sharing feature in iTunes.
• AirPort Time Capsule

  Apple’s AirPort Time Capsule unit isn’t just a wireless remote hard drive for use with the Time Machine backup feature that’s built-in to Mavericks: It can also act as a full AirPort Extreme Base Station. In fact, the wireless specifications for an AirPort Time Capsule unit and an AirPort Extreme Base Station are almost identical.

  The latest 802.11ac standard used by the AirPort Extreme and AirPort Time Capsule delivers a connection that’s several times faster than the old AirPort Base Station’s 802.11b/802.11g/802.11n standards. 802.11ac is also compatible with all the older standards — 802.11b/a/g/n — so I highly recommend that you stick with 802.11ac in the future. It plays well with others, and at warp speed, to boot!

Table 21-2 Apple Wireless Network Base Stations

The names of the Apple Base Stations are irritatingly similar; Apple usually does a better job differentiating their product names. Jot down the name of your model on a sticky note and stick it on your iMac’s Desktop just so that you don’t get confused.

Installing an Apple Base Station is simple:

1. If you have a DSL or cable modem, connect it to the Ethernet LAN port on the Base Station with an Ethernet cable.
2. If you have an existing wired Ethernet computer network using a switch or router, connect it to the WAN (wide area network) port on the Base Station with an Ethernet cable.

   Only the AirPort Extreme and AirPort Time Capsule stations have a WAN port.

3. If you have a USB printer, connect it to the USB port on the Base Station.

   I cover the steps to share a printer in the upcoming section “Sharing a network printer.”

4. Connect the power cable.
5. Switch on your Base Station.
6. Run the installation software provided by Apple on your iMac.

Using non-Apple base stations

If any company other than Apple manufactured your wireless base station, the installation procedure is almost certainly the same. (Naturally, you should take a gander at the manufacturer’s installation guide just to make sure, but I have added many different brands of these devices in the past using essentially the same steps for each one.)

However, I should note that Apple wireless hardware uses a slightly different security encryption standard than most PC wireless hardware, which results in an extra hurdle when connecting to a non-Apple base station with your iMac. (More on this in the next section. For now, just remember that I recommend using Apple wireless hardware with your iMac whenever possible. It’s just a little easier!)

Joining a wireless network

As far as I’m concerned, the only two types of base stations on the planet are Apple and non-Apple (which includes all 802.11ac, 802.11n, and 802.11g Base Stations and access points). In these two sections, I relate what you need to know to get onboard, using either type of hardware.

Apple AirPort Base Stations

To join a wireless network that’s served by any flavor of Apple Base Station, follow these steps on each Mac with wireless support:

1. Click the System Preferences icon on the Dock.
2. Click the Network tab.
3. From the Connection list on the left, click Wi-Fi.

   Note that Wi-Fi may appear labeled as Ethernet 2 instead. Whatever name it’s assigned on your iMac, however, you’ll still see the familiar “Wi-Fi fan” icon next to the port name.

4. Mark the Show Wi-Fi Status in Menu Bar check box.
5. Click the Apply button.
6. Press +Q to quit System Preferences and save your settings.
7. Click the Wi-Fi status icon (which once again looks like a fan) on the Finder menu bar.
8. From the Wi-Fi menu, choose an existing network connection that you’d like to join.

   The network name is the same as the network name you chose when you set up your AirPort Base Station.

9. If you set up a secure network, enter the password you assigned to the network during setup.

By the way, security is always A Good Thing, and I strongly recommend that you enable the password encryption features of your Apple Base Station while installing it. (Luckily, the Apple Base Station setup application leads you through this very process.) In the words of an important Mark’s Maxim:

Keep uninvited guests out of your network! Use your base station’s security features and encrypt your data!

Some wireless networks might not appear in your Wi-Fi menu list. These are closed networks, which can be specified when you set up your AirPort Base Station. You can’t join a closed network unless you know the exact network name (which is far more secure than simply broadcasting the network name). To join a closed network, follow these steps:

1. Select Join Other Network from the Wi-Fi menu.

   To open the menu, click the AirPort status icon (which looks like a fan) on the Finder menu bar.

2. Type the name of the network.
3. If the network is secured with WEP or WPA2 encryption — the two most popular security standards for protecting your data through encryption — click the Security pop-up menu and select which type of encryption is being used.

   WPA2 is a far superior standard, so choose it over WEP whenever possible.

4. Enter the network password, if required.

To disconnect from a Wi-Fi network, click the Wi-Fi menu and either

• Choose Turn Wi-Fi Off.
• Connect to another Wi-Fi network.

  In other words, if you choose another available Wi-Fi network from the Wi-Fi menu, your iMac will automatically drop the previous connection. (You can be connected to only one wireless network at a time, which makes Good Sense.)

Using non-Apple Base Stations

If you’re using your iMac to connect to a non-Apple base station, you might need to follow a specific procedure that takes care of the slightly different password functionality used by standard 802.11b/g/n/ac hardware.

Mavericks can take care of many potential wireless “language barriers” caused by security encryption (the two most common forms are WEP and WPA2), so whether you need to massage your password to connect to your non-Apple base station depends on the specific hardware and encryption system that it uses.

To read or print the latest version of this procedure, fire up Safari and visit http://kbase.info.apple.com/index.html, searching on the number HT1126. (This is the Apple Knowledge Base article number, which you can type in the first search field.) This article provides the details on how to convert a standard wireless encrypted password to a format that your AirPort Extreme hardware can understand.

Wired connections

If you’re installing a wired network, your iMac already comes with most of what you need for joining your new cabled world. You just connect the hardware and configure the connection. Don’t forget that you also need cables and an inexpensive Ethernet switch. (If you’re using an Internet router or other hardware sharing device, it almost certainly has a built-in four- or eight-port switch.)

Connecting iMac hardware to a wired network

Your Ethernet 10/100/1000 port (which looks like a slightly oversized telephone/modem port) is located in the line of ports on the back of your iMac, ready to accept a standard Ethernet Cat5/Cat5E/Cat6 cable with RJ-45 connectors. If you’re connecting to an existing wired network, you need a standard Cat5/Cat5E/Cat6 Ethernet cable of the necessary length. I recommend a length of no more than 25 feet because cables longer than 25 feet are often subject to line interference (which can slow down or even cripple your connection). You also need a live Ethernet port from the network near your iMac. Plug the cable into your iMac and then plug the other end into the network port.

Wired network hardware

If you don’t know your switch from your NIC, don’t worry. Here, I provide you with a description of the hardware that you need for your wired network.

Wired network components

If you’re building your own wired network, you need

• A switch: This gizmo’s job is to provide more network ports for the other computers in your network. They typically come in four- and eight-port configurations.

  As I mention earlier in this chapter, most Internet routers (sometimes called Internet sharing devices) include a built-in switch. If you’ve already invested in an Internet router, before you go shopping for a switch, make doggone sure that the router doesn’t already come equipped with the ports you need!

• A number of Ethernet cables: Exactly how many cables you need is determined by how many computers and networked devices (like network printers) you’re connecting. If you’re working with a Gigabit Ethernet system, you need Cat5E or Cat6 cables. Cat6 cables provide better performance, but they are more expensive.

Naturally, if you’re using a broadband Internet connection on your home network, you also have a DSL or cable modem. These boxes always include a port for connecting to your wired Ethernet network. (If you have one of the new breed of wireless cable or DSL modems — which acts as a wireless base station — don’t panic, because it should also have a wired port for connecting to your existing switch.)

Wired network connections

After you assemble your cables and your router or switch, connect the Ethernet cables from each of your computers to the router or switch and then turn on the device. (Most need AC power to work.) Check the manual that comes with your device to make sure that the lights you’re seeing on the front indicate normal operation. (Colors vary by manufacturer, but green is usually A Good Color.)

Next, connect your cable or DSL modem’s Ethernet port to the WAN port on your switch with an Ethernet cable. If your modem isn’t already on, turn it on now and check for normal operation.

When your router or switch is powered on and operating normally, you’re ready to configure OS X for network operation. Just hop to the upcoming section “Connecting to the Network.” (How about that? Now you can add network technician to your rapidly growing computer résumé!)

Joining a wired Ethernet network

After all the cables are connected and your central connection gizmo is plugged in and turned on, you’ve essentially created the hardware portion of your network. Congratulations! (Now you need a beard and suspenders.)

With the hardware in place, it’s time to configure Mavericks. In this section, I assume that you’re connecting to a network with an Internet router or switch that includes a DHCP server.

Follow these steps on each Mac running OS X that you want to connect to the network:

1. Click the System Preferences icon on the Dock.
2. Click the Network icon (under Internet & Network).
3. From the Connection list on the left, click Ethernet.
4. Open the Configure IPv4 pop-up menu (see Figure 21-3) and choose Using DHCP.

   

5. Click the Apply button.

   The Apply button is grayed out in the figure because my status (in this dialog) is Connected.

   Enjoy the automatic goodness as OS X connects to the DHCP server to obtain an IP address, a subnet mask, a gateway router IP address, and a Domain Name System (DNS) address. (Without a DHCP server, you’d have to add all this stuff manually. Ugh.)

   A few seconds after clicking the Apply button, you should see the information come up. You might also notice that the DNS Server field is empty, but fear not: OS X is really using DNS Server information provided by the DHCP server.

6. Press +Q to quit System Preferences and save your settings.

   You’re on!

Connecting to the Network

All right! The hardware is powered up, the cables (if any) are installed and connected, and you configured Mavericks. You’re ready to start (or join) the party. In this section, I show you how to share data and devices with others on your network.

Sharing stuff nicely with others

It works … by golly, it works! Okay, now what do you do with your all-new shining chrome network connection? Ah, my friend, let me be the first to congratulate you, and the first to show you around! In this section, I cover the most popular network perks. (And the good news is that these perks work with both wired and wireless connections.)

Network Internet connections

If your DSL or cable modem plugs directly into your iMac (rather than a dedicated Internet sharing device or Internet router), you might ponder just how the other computers on your network can share that spiffy high-speed broadband connection. If you’re running a wireless network, it comes to the rescue!

Follow these steps to share your connection wirelessly:

1. Click the System Preferences icon on the Dock.
2. Click the Sharing icon.
3. Click the Internet Sharing entry in the Services list to the left of the pane.
4. From the Share Your Connection From pop-up menu, choose Ethernet.
5. Mark the Wi-Fi check box (in the To Computers Using list).
6. Select the On check box next to the Internet Sharing entry in the Services list.

   Mavericks displays a warning dialog stating that connection sharing could affect other computers on your network. If you intend to share the Internet connection provided on an existing network at your home or office that you didn’t set up, contact your network administrator first! (Best to avoid sowing chaos and disorder.)

7. Click Start in the warning dialog to continue.
8. Click the Close button to exit System Preferences.

Sharing an Internet connection (without an Internet router or a dedicated hardware device) through OS X requires your iMac to remain on continuously. This is no big deal if you’re using your iMac as a web server — and your iMac has absolutely no problem remaining on ad infinitum — but tell others on your network that the svelte iMac must remain on, or they’ll lose their Internet connection! Sharing your Internet using your iMac also requires that you enable the Wake for Network Access check box within the Energy Saver pane in System Preferences.

Don’t forget that you won’t need to configure Internet sharing if your DSL or cable modem connects to a dedicated sharing device or router. That snazzy equipment automatically connects your entire network to the Internet.

Network file sharing

You can swap all sorts of interesting files with other Macintosh computers on your network. When you turn on File Sharing, Mavericks lets all Macs on the network connect to your iMac and share the files in your Public folder. (Note: Sharing across a network is different from sharing a single computer betwixt several people. I cover that environment in Chapter 20.)

Follow these steps to start sharing files and folders with others across your network:

1. Click the System Preferences icon on the Dock.
2. Click the Sharing icon.
3. Select the On check box next to the File Sharing service entry to enable the connections for Mac and Windows sharing.

   Other Mac users can connect to your computer by clicking Go in the Finder menu and choosing the Network menu item. The Network window appears, and your iMac is among the choices. If the other Macs are running Mavericks, your iMac’s shared files and folders appear in a Finder window, and they’re listed under the Shared heading in the Sidebar.

   Windows XP users should be able to connect to your Mac from their My Network Places window, and Vista/Windows 7 users can use the Network window. (Windows 8 users should head to the Network panel instead.) Those lucky Windows folks also get to print to any shared printers you’ve set up. (The following section covers shared printers.)

4. Click the Close button to exit System Preferences.

Mavericks conveniently reminds you of the network name for your iMac at the top of the Sharing pane.

Sharing a network printer

Boy, howdy, do I love describing easy procedures, and sharing a printer on a Mac network ranks high on the list! You can share a printer that’s connected to your iMac (or your AirPort Extreme, AirPort Time Capsule, or AirPort Express Base Station) by following these very simple steps:

1. Click the System Preferences icon on the Dock.
2. Click the Sharing icon.
3. Select the On check box next to the Printer Sharing service entry.
4. From the list at the right of the System Preferences window, select the printer you want to share by clicking the check box.
5. Click the Close button to exit System Preferences.

A printer that you share automatically appears in the Print dialog on other Macs connected to your network.

USE YOUR FIREWALL!

Yep. That’s the only heading in this entire book that’s all uppercase. It’s that important.

The following Mark’s Maxim, good reader, isn’t a request, a strong recommendation, or even a regular Maxim; consider it an absolute commandment (right up there with Get an antivirus application now).

Turn on your firewall now.

When you connect a network to the Internet, you open a door to the outside world. As a consultant to several businesses and organizations in my hometown, I can tell you that the outside world is chock-full of malicious individuals who would dearly love to inflict damage on your data or take control of your iMac for their own purposes. Call ’em hackers, call ’em delinquents, or call ’em something I can’t repeat, but don’t let them in!

Mavericks comes to the rescue again with the built-in firewall within OS X. When you use this, you essentially build a virtual brick wall between you and the hackers out there (both on the Internet and even within your local network). Follow these steps:

1. Click the System Preferences icon on the Dock.
2. Click the Security & Privacy icon.
3. Click the Firewall tab.
4. Click the Turn On Firewall button to activate your firewall.
5. Click the Firewall Options button.
6. Select the Automatically Allow Signed Software to Receive Incoming Connections check box.
7. Select the Enable Stealth Mode check box.

   This is an important feature that prevents hackers from trolling for your iMac on the Internet — or, in normal-speak, searching for an unprotected computer — so it’s much harder for them to attack you.

8. Click OK.
9. Click the Close button to exit System Preferences.

Mavericks even keeps track of the Internet traffic that you do want to reach your iMac, such as web page requests and file sharing. When you activate one of the network features that I demonstrate in the preceding section, Mavericks automatically opens a tiny “hole” (called a port by network types) in your firewall to allow just that type of communication to your iMac. For example, if you decide to turn on File Sharing (as I demonstrate earlier), Mavericks automatically allows incoming file access.

You can also add ports for applications that aren’t on the firewall’s Allow list. These applications include third-party instant messaging (IM) clients, multiplayer game servers, and the like. Depending on the type of connection, Mavericks will often automatically display a dialog prompting you for confirmation before allowing certain traffic, so most folks won’t need to do anything manually.

However, you can add a program manually to your list of allowed (or blocked) Firewall ports. Follow these steps:

1. Click the System Preferences icon on the Dock.
2. Click the Security & Privacy icon.
3. Click the Firewall tab.
4. Click the Firewall Options button.
5. Click the Add button (which bears a plus sign).

   Mavericks displays a standard File browsing sheet.

6. Browse to the application that requires access to the outside world — or the application that you want to block from outside communication — and click it to select it.
7. Click the Add button in the File sheet.

   The application appears in the Firewall list. By default, it’s set to Allow Incoming Connections.

8. If you want to block any incoming communication to the application, click the Allow Incoming Connections pop-up menu and choose Block Incoming Connections instead.
9. Click the Close button to exit System Preferences.