In general, the process of installing a WiFi device begins by connecting the router to the same computer that is attached to your broadband modem; this allows automated configuration sof
Trang 1In general, the process of installing a WiFi device begins by connecting the router to the same computer that is attached to your broadband modem; this allows automated configuration software to obtain the information it needs without any intermediary devices along the way
Initial setup for a wireless router
Here is a typical setup:
1.Turn off the power to your broadband modem.
If there isn’t an on/off switch, remove the power supply to the device
2.Connect the power adapter to the back panel of the wireless router
3.Plug the adapter into an AC outlet
Check that the power LED illuminates
4.Connect an Ethernet cable to the broadband modem
5.Restore the power to the modem.
6.Insert the other end of the Ethernet cable into the WAN (wide area network) port on the back panel of the wireless router
The WAN light should illuminate
7.Insert another Ethernet cable between LAN Port 1 (on the back panel
of the wireless router) and any available Ethernet port on the NIC (network interface card) of the computer you’re going to use to config-ure the WiFi system.
8.Shut down
9.Restart the computer connected to the WiFi router
Let Windows fully load
10.Open your Web browser
Internet Explorer or Mozilla Firefox are examples
11.In the address bar of the browser, type the URL for the built-in setup screen of the wireless router.
For example, type http://192.168.0.1 for most D-Link routers
12.Press the Enter key
To see a list of the standard addresses for setup screens as well as default usernames and passwords from several major makers, see Table 3-2 Depending on your device maker, you may have to enter a user name such
as admin (for administrator), and you may have to enter a password
Consult the instructions for details Once you log in, the home screen of the built-in setup system appears See Figure 3-3
Trang 2Book VIII Chapter 3
Table 3-2 Router Setup Screen Addresses
Router Manufacturer URL Default User Name Default Password
A typical automated process (wizard) includes the option to establish a
password for control of your router I strongly suggest you do so
Choose a password that isn’t related to anything in your personal or busi-ness life and throw in some numbers and special characters This password
is just to control settings made for the router; whatever strange password I come up with I usually write on an index card and place within the box for the router which then goes into my Closet of Old Boxes for Devices Attached
to My Computers
Figure 3-3:
The opening screen of the setup utility for a Linksys wired router
Trang 3Any properly designed piece of network equipment should be compatible with similar or complementary devices made by other manufacturers In my primary system, I have a Motorola cable modem feeding through a D-Link telephone adapter to a Linksys router; elsewhere in the building a Belkin wireless router broadcasts WiFi signals That said, configuring devices some-times is easier when all of your devices wear the same badge Be prepared to push technical support for assistance if you find yourself facing an irrational incompatibility
From this point on, the automated wizard should determine most of your settings by electronically interrogating your broadband modem Among the information it needs to know is if your Internet provider uses a dynamic IP address (the most common configuration for cable modems) or a PPPoE connection (more commonly used by DSL providers) Other options include
a static IP address
✦ A dynamic IP address is one that is automatically assigned to a
com-puter (or a networking device) by a remote server at the Internet provider; this is part of what is called a Dynamic Host Configuration Protocol A dynamic IP address may change at any time if the ISP needs
to reconfigure its system
✦ A static IP address is one that is manually assigned to a computer or
network device by an administrator or ISP If the static address is later changed by the provider, equipment settings must be updated
✦ A PPPoE (Point-to-Point Protocol over Ethernet) is used by some DSL
providers to provide a connection that creates a virtual link between two ends of a connection even though the actual data is still encapsu-lated in packets of digital information
If the system is unable to determine your settings, you will have to instruct it yourself You should be able to find out what sort of configuration you need
by calling your Internet provider or consulting its Web page
If you have selected Dynamic IP Address, you should be offered the option to Clone MAC Address (to automatically copy the MAC address of the network adapter in your computer) You can also type in the MAC address
You can find the MAC address by consulting the Properties page for your NIC
On the other hand, if you need to enter a static IP address, a different screen requests full information including the assigned IP Address, subnet mask, and DNS addresses You should get that information from your ISP to enter the details on this screen
If your ISP uses PPPoE you will need to enter a user name and password for your particular service; again, this should be made available to you by your Internet provider
Trang 4Book VIII Chapter 3
Once the details of the address have been settled, you will need to set — or approve the default for — the SSID and Channel
SSID (Service Set Identifier) is the name of the network Why not call it
“net-work name” instead of a forgettable acronym? Ask the engineers
I strongly recommend that you change the name of the SSID Many routers will be called “default” or be given the moniker of the router manufacturer:
D-Link or Linksys, for example Just think about it: there are a few dozen router makers, with three or four of them owning a major share of the market; the chances of your wireless or wired router being within range of another device of the same is pretty high
The important thing here is not security but identity; you want to be able to quickly recognize your network Give it a name that is recognizable to you but that doesn’t reveal any information you don’t want outsiders to see
Routers have a number of channels they can use, slight variations on their assigned radio frequency Most come delivered to use channel 6 and that may work just fine for you However, if there is more than one WiFi network
in your home or office, or you run into interference from a neighbor’s system
or other wireless devices in your home or office such as wireless telephones, experiment with changing the channel setting for the router here
Securing your wireless network
Now comes the question of security Do you want to allow anyone within reach of your wireless signal to be able to use the network, or worse, eaves-drop on the electronic information that passes between devices? Even worse: If you’ve enabled “sharing” of files or folders, an outsider who gets through the electronic front door may be able to get into the data on the disks of any machine on the network
The only good reason to operate your network wide open is if you’re intention-ally setting up a public hotspot In that case, disable file and folder sharing
The most commonly offered security options follow:
✦ Wired Equivalency Privacy (WEP) To sign on to a network that uses
WEP, you need to know the WEP key, usually a numerical password.
Most routers offer a choice between 64-bit and 128-bit encryption, with 128-bit encryption much more difficult for a hacker to crack
WEP 64-bit codes are ten digits or letters in length, which happens to coincide with the size of an American or Canadian telephone number (without the preceding 1) More secure 128-bit numbers require 26 digits, which may require a bit more planning on your part See if you can come up with a quotation or a name (not yours) that happens to be
Trang 5that length Follow the instructions offered by the router maker to enter and verify a key
One common type of key or password is a telephone number That’s fine, but don’t use your own number or one associated with you On my sys-tems, I use as keys old phone numbers of friends and relatives There is
no way anyone could guess that I’m using the phone number for the Chinese takeout restaurant that was down the block from my office 20 years ago; why do I still remember that number?
✦ WiFi Protected Access (WPA) A newer and more robust form of
secu-rity, WPA is considered by many experts to be an improvement on WEP WPA2, the latest implementation, is included with Windows Vista and Windows XP with Service Pack 2 installed; if your copy of Windows XP has not been updated you should do so for this reason and many others
✦ Media Access Control (MAC) This system functions as if you were
issu-ing keys only to a specified and pre-identified group of users A router based on MAC does not use a password to authenticate users but instead compares the address it finds within each computer’s network interface card to see if it is on the authorized list of users for your net-work If you add a new machine or want to grant a visitor access to your network you will have to sign on to the configuration screen of your router and add a new MAC address to the list
All the instructions I’ve given generally work with a widely varying mix of machines The extra wrinkles come if your system (like mine) has extra devices like a telephone adapter and a wired router
The key here is to configure the newest piece of equipment — the wireless router in this instance — with a direct connection from it to your computer and the incoming feed of your broadband modem Once the device has been configured, you can shut down your network and rewire the connections to enable the other devices
In my system, the wiring goes like this: cable modem to telephone adapter to wired router to directly connected computers The wireless router plugs into one of the ports on the wired router, and my laptop machines communicate with that device and from there onto the wired network
Improving the range of your WiFi network
In the best of circumstances, a WiFi system should operate at speeds approaching that of a wired network, and there should be a perfect circle of reception surrounding the antenna of your wireless router
In the real world things are rarely that perfect All radio signals are sub-ject to these things:
Trang 6Book VIII Chapter 3
✦ Attenuation Loss of strength over distance or because of atmospheric
conditions
✦ Interference Corruption caused by another signal on the same or
nearby frequency
✦ Blockage The inability of a signal to pass through certain materials.
Some walls reduce or even block transmission of radio waves (especially in old offices and some houses that used metal lath to hold plaster) Also capa-ble of blocking signals:
✦ File cabinets
✦ Refrigerators
✦ Other substantial and dense objects
✦ Interference from other wireless devices I’ve already mentioned cordless phones, microwaves, and baby monitors;
you could also run into problems from your neighbor’s wireless network
Another possible element of the system that can affect the quality and reach
of a signal is the antenna design Many routers can transmit and receive sig-nals that move on a flat plane, like all the points of a compass laid flat on a table But the same router may not be as efficient when directing a signal upward and through the ceiling, or downward and through the floor
Adjustments to positioning and settings
Here are some things you can do to enhance the reach of a basic wireless network:
✦ Find the best location for the router In some situations this may be the center of your home or office, but in others the best location might be in
a corner that has a relatively unobstructed “view” of the computers that will seek to use its signal In my setup, my home office is located at one end of our large multistory house; I ran a cable from my office into a room in the center of the house and placed a wireless access point high
up on a shelf there to broadcast everywhere I wanted the signal to go
✦ Make sure your wireless router is not near large metal objects and other obstructions
✦ Keep wireless routers away from transceivers for cordless telephones that use the same 2.4 GHz frequency range You might want to experiment with different cordless phone systems, including those that operate in the higher 5.8 GHz or the lower 900 MHz range to see if this reduces or elimi-nates interference
Trang 7✦ Consider placing a WiFi transmitter high up on a shelf to extend cover-age over obstructions and into upper floors
✦ Experiment with alternate channel settings for the router Most WiFi equipment comes preset to use a particular channel, but this may be the same one used by other routers or by other wireless equipment Try making adjustments to the channel through its configuration screen
✦ Keep your wireless router current by downloading and installing any updated firmware for your router; check the web site for the manufac-turer of your device every six months or so You should also make sure you are using the most current device driver for Windows to enhance your computer’s ability to control networks
Updating and enhancing your wireless hardware
Here are some things you can purchase to boost your wireless network to the next level
Upgrade your wireless hardware so that it matches the capabilities of your newest and most advanced laptop (Remember that a laptop with the latest and greatest WiFi equipment will communicate no faster or better than the router or wireless access point’s top speed.) Current laptops come equipped with 802.11g or 802.11n WiFi circuitry; if your router is
an 802.11b device, that is the speed you’ll get The good news: prices for wireless equipment, like most technology, continue to go down even as capabilities improve
Upgrade the standard antenna on your router from the omnidirectional design provided by most manufacturers An omni antenna is meant to send the signal in all directions; a directional signal allows you to aim the signal where you need it Check with the maker of your router, or electronics sup-pliers, for information about purchasing a replacement antenna
Boost the capabilities of an older laptop’s wireless hardware by disabling its built-in WiFi circuit and antenna and installing an external adapter that uses the latest technology and has a larger antenna External WiFi devices may plug directly into your laptop’s USB port or attach to it by cable You can also purchase adapters that plug into a PC Card or ExpressCard slot
Repeat or expand your signal You can add a wireless amplifier (called a repeater or a range expander) that picks up the signal from your router and then retransmits it The best use of this sort of device is to place it some-where near the edge of your existing signal; it then rebroadcasts the signal
to cover more territory See Figure 3-4
Trang 8Book VIII Chapter 3
Courtesy of Linksys
Setting up a Wireless Network in Windows
To this point this chapter focuses entirely on the hardware side of the equa-tion: the WiFi transceiver in your laptop and the wireless router or access point in your home or office network The third leg of the stool is the config-uration of your laptop to communicate with a wireless network
Once again, this is an area that has gone from almost hopelessly complex back
in the day before networking was a part of Windows to almost ridiculously easy now that wired and wireless communication has been totally integrated into the operating system For users of Windows XP and Windows Vista, once the hardware has been properly set up you’re just a few clicks (and a power switch) away from getting online or on the network without benefit of wires
With the arrival of Windows XP Service Pack 2 and later, Windows Vista, Microsoft has put forth a set of technologies under the umbrella name of Windows Rally Included amongst them is Windows Connect Now (WCN), a specification and design intended to automate the configuration of devices
in a wireless network
Microsoft envisioned that manufacturers of wireless equipment, including routers, access points, and attached devices would fully implement this stan-dard but as of 2008 the embrace has been less than complete In theory, the technology is built around the transfer of settings from device to device on a flash memory card — routers and other devices would have a USB port for that purpose Once elements of the network have received their instructions, the flash memory card would be removed and wireless communication would proceed Windows Connect Now is a fine idea, and its time may come
But for most users the best advice is this: Buy good quality equipment from a manufacturer that provides a reasonable level of customer support and plan
on following the instructions for your particular device carefully and call-ing for help if you need it
Figure 3-4:
One example of
a repeater is the Linksys Wireless-G Range Extender
Trang 9In the following sections I concentrate on the utilities provided by Microsoft
as part of current versions of Windows At the end of this chapter I will give you a glimpse at one of the highly capable automated wireless configuration tools offered by a laptop maker for its own line of machines
Windows Vista wireless wizardry
Under Windows Vista, once the hardware is in place and powered up, here’s
how to set up the software side of wireless networking
1.Turn on the power switch for the built-in WiFi circuitry of your laptop.
For setup purposes only, you may have to reroute Ethernet wiring so your laptop (or the desktop that controls the network) is directly linked
to the wireless router That way it can make settings on the device’s configuration screen Consult the instructions that come with the WiFi device for details
2.Run the Set up a Wireless Router or Access Point wizard on the com-puter attached to the router
3.Click Start ➪ Control Panel ➪ Network and Internet ➪ Network and
Sharing Center
4.In the left pane, click Set Up a Connection or Network
5.Click Set Up a Wireless Router or Access Point
The wizard walks you through the steps
If you want to share files and printers that are in computers or attached
to your network, set your network location type to Private and turn on network discovery, file sharing, and printer sharing
On/Off
There are several reasons your laptop has one
or more ways to turn off the power to built-in WiFi circuitry One is to save battery power when it is not needed A second reason is to allow you to comply with instructions from air-lines and certain highly secretive and demand-ing government agencies that may not want you to be able to communicate in places they control That said, it is often difficult to find the on/off switch on many laptops; I will be the first
to admit that I once suffered through an hour of waiting on the telephone to speak with a sup-port technician in a far-off land in order to learn that the reason my new laptop was not work-ing with the wireless network was that the switch — mentioned in the manual but not shown on any diagrams — was turned off And so, the critical advice: Find the switch and learn how to use it
Trang 10Book VIII Chapter 3
Testing the network
You should test the setup for the network on each computer that is author-ized to communicate with it
Do this on each machine: Click Start ➪ Network A window opens and you should see icons for the computer you’re testing, as well as those for each of the other computers and devices that you have added to the network
Any time you have a mix of versions of Windows on your network, it may take a period of time — as much as several minutes — for some machines running different versions to show up on particular network display
If the computer you are checking has an attached printer, the icon for that device may not be shown on other computers until you have enabled printer sharing for the network and have shared that specific printer (Printer shar-ing is available in all versions of Windows Vista except for the most basic, uncommon version: Windows Vista Starter.)
Automatically adding a device to an existing network
A very easy way to automatically configure a laptop to work with a network
is to use the facilities of Windows Vista to copy the necessary settings to a flash drive
Here’s how to do this under Windows Vista:
1.Turn on a computer that is successfully communicating with a network.
2.Plug a flash memory drive into a USB port on the computer.
The AutoPlay dialog box appears onscreen
3.Click Wireless Network Setup Wizard.
4.Follow the onscreen directions to copy settings to the flash memory
5.When the task is completed, remove the flash memory from the computer.
6.On the laptop you want to add to the wireless network, click Start ➪ Control Panel
7.Click Network and Internet
8.In the Network and Sharing Center, click Add a Device to the Network.
9.Follow the instructions in the wizard.