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Secure Your Home Wireless Network: Part V

Here are Part I, Part II, Part III, and Part IV.

WPA Encryption Example

To compare enabling WEP encryption to how WPA encryption is enabled, let's take an example of WPA (this time, we pick 8F37ahr43K as our example pre-shared key). Enabling WPA encryption is a lot like enabling WEP encryption, except you must make one additional decision: You must decide how long an encryption key will be allowed to be used before a new key is assigned. The lower the value, the less time a hacker has to try to "crack" the key. For example if you set the value to 1800 seconds (which is 30 minutes for you nonmath majors), a key is used for 30 minutes and then the wireless router and wireless NIC create a new key. If a hacker "cracks" the key within 30 minutes (which is pretty tough to do), the key will only be valuable for the remainder of the 30 minutes before it is switched to an entirely new key, and the hacker would have to start all over.

First, here's an example of setting up WPA on the wireless router:

  1. On the Wireless Security subtab again (See Figure 20), select Pre-Shared Key on the line labeled Security Mode. (On some Linksys products, the selection is called WPA Pre-Shred Key).
  2. Select either TKIP (For WPA1) or AES (for WPA2). If your wireless router and all wireless NICs support AES mode, select it because it is more secure. If any of them do not, select TKIP. You cannot configure some with TKIP and some with AES.
  3. On the line labeled WPA Shared Key, enter the pre-shared key you made up (in our example, 8F37ahr43K).
  4. On the line labeled Group Key Renewal, enter the number of seconds that you want the key to be used before changing it (See Figure 20). We chose 1800 (which is 30 minutes) for this example.
  5. Click Save Settings.

Figure 20. Enabling WPA Encryption on the Wireless Router

Very Important: So how long should you set the key renewal period for? There is no great answer, although if you have the value set too low (1 to 2 minutes, for example) it could cause connectivity issues for some NICs. We recommend following manufacturer recommendations (or defaults).

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