tailieunhanh - CompTIA Network+ Certification Study Guide part 23

CompTIA’s Network+ certification Study Guide part 23 is a globally-recognized, vendor neutral exam that has helped over 235,000 IT professionals reach further and higher in their careers. The 2009 Network+ exam (N10-004) is a major update with more focus on security and wireless aspects of networking. Our new study guide has been updated accordingly with focus on network, systems, and WAN security and complete coverage of today’s wireless networking standards. | 206 CHAPTER 5 Wireless Networking If the network is encrypted the hacker will start by determining the physical location of the target. NetStumbler has the ability to display the signal strength of the discovered networks. Utilizing this information the attacker only needs to drive around and look for a location where the signal strength increases and decreases to determine the home of the wireless network. To enhance their ability to locate the positions of a wireless network attackers can use directional antennas to focus the wireless interface in a specific direction. An excellent source for wireless information including information on the design of directional antennas is the Bay Area Wireless Users Group . Note Keep in mind that the most popular wireless network security scanning tools are Ethereal NetStumbler AiroPeek and Kismet. This will help you to analyze wireless networks in the field. Each tool has its benefits so you may want to try them all if you have access to them. Protecting Against Sniffing and Eavesdropping As networking technology matured wired networks were able to upgrade from repeaters and hubs to a switched environment. These switches would send only the traffic intended for a specific host over each individual port making it difficult although not impossible to sniff the entire network s traffic. Unfortunately this is not an option for wireless networks due to the nature of wireless communications. The only way to protect wireless users from attackers who might be sniffing is to utilize encrypted sessions wherever possible SSL for e-mail connections Secure Shell SSH instead of Telnet and secure copy SCP instead of File Transfer Protocol FTP . To protect a network from being discovered with NetStumbler it is important to turn off any network identification broadcasts and if possible close down the network to any unauthorized users. This prevents tools such as NetStumbler from finding the network. However the knowledgeable .