tailieunhanh - Networking: A Beginner’s Guide Fifth Edition- P35

Networking: A Beginner’s Guide Fifth Edition- P35:I have run into many people over the years who have gained good even impressive working knowledge of PCs, operating systems, applications, and common problems and solutions. Many of these people are wizards with desktop computers. | 152 Networking A Beginner s Guide the employees know each other. An example of a social engineering technique is calling an employee and posing as a network administrator who is trying to track down a problem and who needs the employee s password temporarily. Another example is to sort through a company s trash looking for records that might help the culprit crack a password. Make sure to instruct your company s employees carefully to never give out their password to anyone over the telephone and also that IT people usually never need to ask anyone s password. Back-Door Threats Back-door threats are often directed at problems in the network operating system itself or at some other point in the network infrastructure such as its routers. The fact is that all network operating systems and most network components have security holes. The best thing you can do to prevent these problems is to stay current with your software and any security-related patches that are released. You should also periodically review new information about security holes discovered in the software you use. TIP Don t rely on the vendor s web site for the best information about software security holes. A good web site to use to stay current on security holes is the one maintained by the Computer Emergency Response Team CERT located at http . Aside from finding advisories on security holes you can also discover much valuable security information on the site. Web servers are a frequent target for crackers. Consider the following tips to help protect against threats to web servers You re better off if you can host the company s web site on an external server such as an Internet service provider s ISP s system rather than on your own network. Not only is an ISP better able to provide the server service 24 hours a day 7 days a week but it also probably has better security. Also you don t need to worry about allowing web server access to your LAN from outside the company which can sometimes