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wireles network hacks mods - briere D.

briere D. wireles network hacks mods - Wiley publishing, 2005. - 387 p.
ISBN: 0-7645-9583-0
Download (direct link): wirelesnetworkhacks.pdf
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^ Keeping people whom you don’t want on your network off of it so that they can’t access your file servers, Internet connection, and so on. This is done by requiring users to provide a password to get “attached” to the wireless network.
^ Keeping people from intercepting and “reading” the data traveling over your network. This is done by encrypting or scrambling your data as it travels wirelessly.
WEP is better than nothing, but it turns out to be a not particularly good way of securing a network. The keys used to scramble data in WEP are not all that robust, and it didn’t take hackers (the good guys interested in figuring out how things work) and crackers (the bad guys who want to get into your business) long to figure out how to “break” the key and therefore defeat WEP.
There are two efforts to remedy this problem that you should be aware of. Both the IEEE — with a new standard called 802.11i — and the Wi-Fi Alliance — with a protocol called WPA — have stepped in to fill the security gap:
802.11i: Ratified in late 2004, 802.11i is the IEEE’s newest and most robust security standard. The name can confuse some folks — because it’s an 802.11x standard, many assume that it’s another PHY standard like 802.11b or g. In fact, 802.11i only covers the security portions of the wireless LAN and can be used (if the equipment allows it) with 802.11b, g, or a networks.
Part I: Making Your World Wireless
802.11i provides a lot of security improvements, but the biggest ones revolve around the improved encryption keys used — either TKIP (Temporal Key Integrity Protocol) or AES (Advanced Encryption Standard). AES is the stronger of these two protocols — it’s used by the U. S. government for its own communications, so you can feel pretty confident that no bad guy is going to be able to eavesdrop on your Wi-Fi network.
As we write this book, 802.11i-certified gear is starting to hit the streets, mainly focused on enterprise wireless equipment, not for the home.
WPA: As the IEEE was completing the 802.11i standard, the folks at the Wi-Fi Alliance put together a security standard called WPA (or Wi-Fi Protected Access) that provided an interim improvement over WEP by using the more secure TKIP encryption key. Now that 802.11i has been finalized, the Alliance has come up with a new version of WPA — called WPA2 — which provides the full level of security provided by the AES standard in 802.11i.
The WPA standards include both personal and enterprise variants of the standard. The personal variants (the kind you find on any home Wi-Fi gear) let you set the encryption key by means of a shared password (one that you make up yourself and share with anyone who is on the network), whereas the enterprise variants use a separate system called 802.1x (which uses a special server to ascertain a user’s identity and provide her with the encryption key).
At a bare minimum, you should always turn on WPA on your wireless network (unless you’re deliberately sharing access publicly, as we describe in Chapter 12). If you’re buying new equipment, make sure it supports WPA2.
Gimme an “e” for service quality
Besides security, another wireless LAN shortcoming has been the lack of a QoS (or quality of service) mechanism in any of the standards. Sounds like some sort of techie mumbo-jumbo, no? It is, but it’s important: QoS is what allows your wireless LAN to “look” at the data being sent across the network and decide which bits and bytes need to be prioritized and which don’t.
Ultimately, a QoS system should be able to, for example, make sure that the VoIP (Voice over Internet Protocol) phone call you’re making gets the highest priority, and that the iTunes music stream gets the next highest priority, and so on down the line (all the way down to the real low priority stuff, like that e-mail from your mother-in-law).
802.11a/b/g wireless LANs don’t, by nature, have any QoS mechanism. All the data you send across your network carries the same priority, no matter what type of traffic it is. This isn’t really a problem for most data applications, such as e-mail and Web surfing, but it can be a real issue for multimedia uses of the
Chapter 2: Wireless Network Basics
network such as audio, video and voice. As you’ll see throughout WNH&M For Dummies, these multimedia applications are where all the cool wireless networking fun begins!
The IEEE and the Wi-Fi Alliance are both on top of the problem, with standards efforts to add QoS mechanisms into wireless LAN gear. Like the 802.11i/WPA efforts we discussed in the previous section, these efforts are designed to work with rather than replace existing wireless LAN standards like 802.11a/b/g.
Two related QoS efforts are in place, one you can use today, and one that you have to wait for:
802.11e: This is the IEEE standard for Wi-Fi QoS. As we write, this is still a draft standard — meaning it’s close to being finalized, but it is not yet an official standard. What this means to you is simply this: You can buy equipment that incorporates the draft standard, but it’s possible that the final standard, when it comes out, will be changed in some unanticipated way that makes your pre-standard equipment non-compliant.
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