tailieunhanh - Suse Linux 9.3 For Dummies- P22

Suse Linux For Dummies- P22:This part is all about getting you started on your way to a lasting relationship with SUSE Linux. Before you can begin your SUSE Linux experience, I spend a chapter explaining what SUSE Linux is and what you can do with SUSE Linux (pretty much anything you can do with a PC that runs Windows). | Chapter 19 Securing SUSE Linux 295 Term Description War-dialing Simple programs that dial consecutive phone numbers looking for modems. War-driving A method of gaining entry into wireless computer net works using a laptop antennas and a wireless network card that involves patrolling locations to gain unauthorized access. Worm A self-replicating program that copies itself from one computer to another over a network. Practicing Good Host Security Host is the techie term for your Linux system especially when you use it to provide services on a network. But the term makes sense even when you think of the computer by itself it s the host for everything that runs on it the operating system and all the applications. A key aspect of computer security is to secure the host. In this section I take you through a few key steps to follow in securing your SUSE Linux host. These steps include installing operating system updates following steps that I outline in Chapter 18 protecting passwords and protecting the files and directories. Making passwords expire Obviously leaving passwords lying around where anyone can get at them even if they re encrypted is bad security. So instead of storing passwords in the etc passwd file which any user can read Linux now stores them in a shadow password file etc shadow. Only the superuser root can read this file. The etc shadow file also includes fields that control when each password expires. You can use the chage command to change the password-expiration information. For starters you can check a user s password-expiration information by using the chage command with the -l option as follows in this case you have to be logged in as root chage -l root This command displays expiration information including how long the password lasts and how often you can change the password. Please purchase PDF Split-Merge on to remove this watermark. 296 Part IV Becoming a SUSE Wizard If you want to ensure .