Suse Linux 9.3 For Dummies- P11

Suse Linux 9.3 For Dummies- P11:This part is all about getting you started on your wayto a lasting relationship with SUSE Linux. Before youcan begin your SUSE Linux experience, I spend a chapterexplaining what SUSE Linux is and what you can do withSUSE Linux (pretty much anything you can do with a PCthat runs Windows).
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Suse Linux 9.3 For Dummies- P11 130 Part II: Test Driving SUSE Understanding Wired Equivalent Privacy (WEP) The 802.11 standard includes Wired Equivalent Privacy (WEP) for protecting wireless communications from eavesdropping. WEP relies on a 40-bit or 104-bit secret key that is shared between a mobile station (such as a laptop with a wire- less Ethernet card) and an access point (also called a base station). The secret key is used to encrypt data packets before they transmit and an integrity check is performed to ensure that packets are not modified in transit. The 802.11 standard does not explain how the shared key is established. In practice, most wireless LANs use a single key that is shared between all mobile stations and access points. Such an approach, however, does not scale up very well to an environment such as a college campus because the keys are shared with all users — and you know how it is if you share a “secret” with hundreds of people. That’s why WEP is typically not used on large wireless networks such as the ones at universities. In such wireless networks, you have to use other security approaches such as SSH (Secure Shell) to log in to remote systems. WEP, however, is good to use on your home wireless network. WEP has its weaknesses, but it’s better than nothing. You can use it in smaller wireless LANs where sharing the same key among all wireless stations is not an onerous task. Work is underway to provide better security than WEP for wireless networks. A standard called 802.11i is in the works that provides better security through public-key encryption. While the 802.11i standard is in progress, the Wi-Fi Alliance — a multivendor consortium that supports Wi-Fi — has devel- oped an interim specification called Wi-Fi Protected Access (WPA) that’s a precursor to 802.11i. WPA replaces the existing WEP standard and improves security by making some changes. For example, unlike WEP (which uses fixed keys), the WPA standard uses something called the Temporal Key-Integrity Protocol (TKIP), which generates new keys for every 10K of data transmitted over the network. TKIP makes WPA more difficult to break. You may want to consider wireless products that support WPA while waiting for products that implement 802.11i. Setting up the wireless hardware To set up the wireless connection, you need a wireless access point and a wireless network card in each PC. You can also set up an ad hoc wireless network among two or more PCs with wireless network cards, but that is a stand-alone wireless LAN among those PCs only. In this section, I focus on the scenario where you want to set up a wireless connection to an estab- lished LAN that has a wired Internet connection through a cable modem or DSL.Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Chapter 8: Setting Up an Ethernet LAN with Wireless Access 131 In addition to the wireless access point, you also need a cable modem or DSL connection to the Internet, along with a NAT router/hub. Figure 8-4 shows a typical setup for wireless Internet access through an existing cable modem or DSL connection. As Figure 8-4 shows, the LAN has both wired and wireless PCs. In this exam- ple, either a cable or DSL modem connects the LAN to the Internet through a NAT router/hub. Laptops with wireless network cards connect to the LAN through a wireless access point attached to one of the RJ-45 ports on the hub. To connect desktop PCs to this wireless network, you can use a USB wireless network card (which connects to a USB port). If you have not yet purchased a NAT router/hub for your cable or DSL connec- ...