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Setting Up an 802.11b Home Wireless Network
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Configuring Wireless Devices

Once all of the necessary devices are installed, it's not difficult to test the wireless connection. Your wireless adapter comes with utilities to change its settings. In my case, I'm using the software that came with the Linksys PCMCIA card.

Examining the Link Quality and Signal Strength of the Wireless Connection
Figure 8. Examining the Link Quality and Signal Strength of the Wireless Connection

Under the Link Info tab, it shows that my link quality and signal strength are pretty good. In general, the closer the wireless adapter is to the wireless access point, with a clear line-of-sight, the better the signal quality.

Specifying the Mode and SSID for the Wireless Network
Figure 9. Specifying the Mode and SSID for the Wireless Network

Under the Configuration tab, you can select the wireless mode--Infrastructure or Ad Hoc. Infrastructure mode uses wireless access points, while Ad Hoc mode is for peer-to-peer communication. In my case, I selected Infrastructure mode.

The SSID (Service Set Identifier) acts like a "password." All wireless devices wanting to participate in a particular wireless network must specify a SSID. The wireless devices will not be able to participate in this network if the SSID is not specified (or if it is not stated correctly). In my case, the default SSID is "linksys." You are strongly advised to change this to something else. See the next section on SSID.

By default, encryption is not enabled. Encryption is important, because hackers equipped with the necessary devices can sniff the packets transmitted by the wireless network, thereby compromising your data. Wired Equivalent Privacy (WEP) is a protocol used for encrypting packets on a wireless network. It uses a 64-bit (or 256-bit, depending on the vendor) shared key algorithm. Using WEP will increase the protection on your data, but doing so will reduce the effective data rates.

Some Guidelines for Wireless Networking

Though your new wireless network allows you to have the freedom to surf the Internet anywhere in your house, it's also good news for your close neighbors, because some of them can now surf the Internet for free! Unlike a wired network, where you need to have physical access to a network point in order to gain access to the network, a wireless network extends beyond the four walls of your house.

Most wireless access points and routers provide a Web-based configuration program for configuring the wireless access point. Below are some guidelines for "securing" your wireless network:

  • Change the default SSID. Most people don't even bother to change the default SSID provided by a wireless access point. If your neighbor knows that you are using a Linksys wireless access point (say, by seeing the boxes you throw away), they could easily try the default SSID. Always change the SSID to something obscure, and never try to use your company name or your personal name. These names are too easy to guess.
  • Disable SSID broadcast. By default, most wireless access points will broadcast the SSID to all wireless devices; anyone with a wireless network card can detect the SSID you use in your network and gain access to your network.
  • Use MAC address filtering. If you have a small number of users in your wireless network (which is usually the case), you can use MAC address filtering. With MAC address filtering, you enter the MAC address of your network card and manually enter this number into your wireless access point. Only MAC addresses that have been registered with the wireless access point are able to gain access to your network. You can usually locate the MAC address of your network card on the device itself.
  • Always change the default user name and password for your wireless access point. It's too easy for people to guess the default user names and passwords used in wireless access points.
  • Turn off DHCP. Use static IP addresses if the number of users on the network is small. Turning off DHCP will prevent wireless sniffers from seeing the IP addresses being used.
  • Refrain from using the default IP subnet. Most wireless routers use the default 192.168.1.0 network. It is easy for people to guess the IP addresses used and illegally gain access to the network.
  • Use WEP for encryption of packets. If you are concerned about the confidentiality of information transmitted by your wireless network, you may wish to enable WEP encryption. Though WEP has been proven to be "crackable," it still acts as a deterrent against packet sniffing for everyone but ardent hackers.

Summary

A common concern about "going wireless" is 802.11's limited data transfer rate. While the theoretical speed of 11Mbps already seems slow compared to Ethernet's 100Mbps (and most cable/ADSL/DSL modems don't even come close to 11Mbps anyway), this isn't a problem if your primary motivation is to access the Internet. 802.11b's bandwidth is more than sufficient for Web work.

However, if you're designing a wireless network in a large work environment (where you may have a faster connection to the Internet) that requires a much higher data rate, you should also take a look at my article that looks at two faster standards that are now in place-802.11a and 802.11g. Have fun with your wireless network!

Wei-Meng Lee (Microsoft MVP) http://weimenglee.blogspot.com is a technologist and founder of Developer Learning Solutions http://www.developerlearningsolutions.com, a technology company specializing in hands-on training on the latest Microsoft technologies.

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