Click the Add Features link.

viii | Illustrated Book Tour www.wiley.comcollegemicrosoft or call the MOAC Toll-Free Number: 1+888 764-7001 U.S. Canada only Understanding Wired and Wireless Networks | 55 The cable that connects these two pieces of equipment has the individual wires permanently punched down so that they are immovable. The front of a patch panel simply has a lot of RJ45 ports. The patch panel works great if a computer is moved to a different area of an office; the patch cable can simply be moved to the correct port on the patch panel. The tools necessary to make the connections between patch panels and RJ45 jacks include a cutting tool, a wire stripper, a punch down tool, and a testing device known as a continu- ity tester, which tests all of the pins of a connection one by one. The tester lets you know whether any of the pins are mis-wired. It does this by testing the entire cable from end to end. The testing device is connected to one end of the run, and a terminating device connects to the other end; signals are bounced back and forth on every wire or pin. These last two tools are illustrated in Figure 3-6. Generally, twisted-pair cables can be run 100 meters before the signal degrades to such a point that it cannot be interpreted by the destination host. This is known as attenuation. If a cable needs to be run farther, a signal repeater, a hub, or switch can be used. Otherwise, fiber optic cable is the solution because it can be run much farther than twisted-pair cable. Figure 3-5 Patch panel and RJ45 jack Back of Patch Panel RJ45 Jack Figure 3-6 Punch down tool and continuity tester Punch down Tool Continuity Tester Twisted-pair cables are categorized according to the frequency at which they transmit signals and their data transfer rate or speed. Table 3-2 describes the different categories of twisted- pair cable and the types of network speed they can accommodate. Defining Networks with the OSI Model | 37 1. Open the command prompt. 2. Type ipconfig. This will display your IP address, for example, 192.168.1.1. The IP address is developed from the Internet Protocol IP that resides on layer 3 of the OSI model. Jot down your IP address and the IP address of a different computer on the network. 3. Ping the other computer’s IP address by typing ping [ip address], for example, ping 192.168.1.2. Make sure you can get replies from the other computer. Ping utilizes the Internet Control Message Protocol ICMP to send test packets to other computers; this is also a network layer protocol. Notice the size of the replies you receive; by default, they should be 32 bytes each.

4. Type arp –a to view the IP address to MAC address table. This table should now show

the IP address you just pinged. This table is known as the Address Resolution Protocol table, or ARP table. The Address Resolution Protocol is another layer 3 protocol that resolves or translates IP addresses to MAC addresses, allowing connectivity between the layer 3 IP system and the layer 2 Ethernet system.

5. Use Wireshark to capture and analyze ICMP packets as follows:

a. Download and install the Wireshark protocol analyzer previously known as

Ethereal from: http:www.wireshark.org. At the time of the writing of this book, the latest stable version is 1.2.8. Install WinPCap as part of the Wireshark installation. b. Go back to the command prompt and run a continuous ping to another computer, for example, ping –t 192.168.1.2. Verify that you get replies, and leave the command prompt open and pinging the other computer while you complete the packet capture.

c. In the Wireshark utility, select the interface that serves as your main network

adapter from the Interface List. This will start the capture of data from that network adapter.

d. After a minute or so, stop the capture by clicking Capture on the menu bar and

selecting Stop. e. View the list of captured packets in the top half of the screen. In the Protocol col- umn, you should see many ICMP packets. Select one that says “reply” in the Info. column. When you do so, the packet’s information should show up in the middle win- dow pane, similar to Figure 2-5. The dark blue packet numbered 98 in the figure is the highlighted packet. Now, let’s drill down to see the details of the packet. Hardware-based and personal firewalls can possibly block some of the following tests and exercises. You might need to disable one or more firewalls to complete the exercises properly. TAKE NOTE Figure 2-5 Wireshark packet capture Understanding Wired and Wireless Networks | 63 EXAMINE WIRELESS NETWORKING SETTINGS GET READY. In the following exercise, we will access the D-Link DIR-655 emulator and show some standard wireless configurations. To do so, perform these steps:

1. Log in to the DIR-655 emulator and view basic settings:

a. Connect to a router. The username cannot be changed, and the password is

blank, meaning there is no password. This displays the main Device Informa- tion page. Examine this page. Note the LAN IP address of the device. It should be 192.168.0.1, the default for D-Link WAPs. If a client wants to connect to this device, it has to be confi gured via DHCP or statically, but it will need to be on the 192.168.0 network.

b. Scroll down and examine the wireless settings. Wireless should be enabled by

default. Note the mode, channel width, channel used, and so on.

2. Modify the SSID:

a. Click the Setup link on the top banner.

b. Click the Wireless Settings link on the left side.

c. Click the Manual Wireless Network Setup button. This should display the

Wireless page. d. Look for the Wireless Network Name. This is the SSID. The default for D-Link devices is none other than dlink. It is highly recommended that you modify the default SSID on any WAP. Change it now to something a bit more complex. 3. Modify the wireless configuration:

a. Examine the 802.11 Mode drop-down menu. Note the variety of settings. Mod-

ify this so that it says 802.11n only.

b. Deselect the Enable Auto Channel Scan checkbox. This should enable the

Wireless Channel drop-down menu. Select channel 11, which is centered at 2.462 GHz. Subsequent WAPs should be set to channel 6 and channel 1 in order to avoid channel overlapping.

c. Modify the Channel Width setting to 40 MHz. This will incorporate channel

bonding.

4. Enable encryption:

a. At the Security Mode drop-down menu, select WPA-Personal. This should

display additional WPA information. You would only select WPA-Enterprise if you had the aforementioned RADIUS server available.

b. Scroll down, and in the WPA Mode drop-down menu, select WPA2 Only.

c. In the Cipher Type drop-down menu, select AES.

d. Finally, type in a complex Pre-Shared Key. This is the pass-phrase that clients

need to enter in order to connect to the WLAN. This is the highest level of security this device offers aside from WPA-Enterprise. Your configuration should look similar to Figure 3-8.

5. Disable the SSID:

a. When all clients are connected to the WAP, the SSID should be disabled. This

will not allow new connections to the WAP unless the person knows the SSID name, but computers that have already connected may continue to do so.

b. To do this, click the Invisible radio button in the Visibility Status fi eld.

Photos Step-by-Step Exercises Take Note Reader Aid