mspress 70 270 winxp professiona phần 5 pps

10-45 6. Click Limit Disk Usage To. 7. What is the default disk space limit for new users? 8. Click Do Not Limit Disk Usage. If you want to place the same quota limit on all users of this computer, you use the Limit Disk Usage To option. 9. Select the Deny Disk Space To Users Exceeding Quota Limit check box. 10. Select the Log Event When A User Exceeds Their Quota Limit and Log Event When A User Exceeds Their Warning Limit check boxes, and then click Apply. Windows XP Professional displays the Disk Quota dialog box, telling you that you should enable the quota system only if you will use quotas on this disk volume and warning you that the volume will be rescanned to update disk usage statistics if you enable quotas. 11. Click OK to enable disk quotas. 12. What happens to the quota status indicator?  To configure quota management settings for a user 1. In the Quota tab of the Local Disk (C:) Properties dialog box, click Quota Entries. Windows XP Professional displays the Quota Entries For Local Disk (C:) dialog box. 2. Are any user accounts listed? Why or why not? 3. On the Quota menu, click New Quota Entry. Windows XP Professional displays the Select Users dialog box. 4. In the Name text box, type User5, and then click OK. Windows XP Professional displays the Add New Quota Entry dialog box. 5. Click Limit Disk Space To. What are the default settings for the user you just set a quota limit for? Lesson 3 Managing Disk Quotas 10-46 Chapter 10 Managing Data Storage 6. Increase the amount of data that the user can store on drive C by changing the Limit Disk Space To setting to 10 MB and the Set Warning Level To setting to 6 MB. 7. Click OK to return to the Quota Entries For Local Disk (C:) window. 8. Close the Quota Entries For Local Disk (C:) window. 9. Click OK to close the Local Disk (C:) Properties dialog box. 10. Log off. 11. Log on as User5. 12. Start Windows Explorer and create a User5 folder on drive C. 13. Insert the CD-ROM you used to install Windows XP Professional into your CD- ROM drive. 14. If a dialog box appears as a result of inserting the CD-ROM, close it. 15. Copy the i386 folder from your CD-ROM to the User5 folder. Windows XP Professional begins copying files from the i386 folder on the CD- ROM to a new i386 folder in the User5 folder on drive C. After copying some files, Windows XP Professional displays the Error Copying File Or Folder dialog box, indicating that there is not enough room on the disk. 16. Why did you get this error message? 17. Click OK to close the dialog box. 18. Right-click the User5 folder, and then click Properties. Notice that the Size On Disk value is slightly less than your quota limit of 10 MB. 19. Delete the User5 folder. 20. Close all open windows and log off. Exercise 2: Disable Quota Management 1. Log on with an account that is a member of the Administrators group. 2. Start Windows Explorer. 3. Right-click the drive C icon, and then click Properties. Windows XP Professional displays the Local Disk (C:) Properties dialog box with the General tab active. 4. Click the Quota tab. 10-47 5. In the Quota tab, clear the Enable Quota Management check box. All quota settings for drive C are no longer available. 6. Click Apply. Windows XP Professional displays the Disk Quota dialog box, warning you that if you disable quotas, the volume will be rescanned if you enable them later. 7. Click OK to close the Disk Quota dialog box. 8. Click OK to close the Local Disk (C:) Properties dialog box. 9. Close all windows and log off Windows XP Professional. Lesson Review Use the following questions to help determine whether you have learned enough to move on to the next lesson. If you have difficulty answering these questions, review the material in this lesson before beginning the next lesson. You can find answers to these questions in the “Questions and Answers” section at the end of this chapter. 1. What is the purpose of disk quotas? 2. Which of the following statements about disk quotas in Windows XP Professional is correct? (Choose the correct answer.) a. Disk quotas track and control disk usage on a per-user, per-disk basis. b. Disk quotas track and control disk usage on a per-group, per-volume basis. c. Disk quotas track and control disk usage on a per-user, per-volume basis. d. Disk quotas track and control disk usage on a per-group, per-disk basis. 3. Which of the following statements about disk quotas in Windows XP Professional is correct? (Choose all that apply.) a. Disk quotas can be applied only to Windows XP Professional NTFS volumes. b. Disk quotas can be applied to any Windows XP Professional volume. c. You must be logged on with the Administrator user account to configure default quota management settings. d. Members of the Administrators and Power Users groups can configure quota management settings. Lesson 3 Managing Disk Quotas 10-48 Chapter 10 Managing Data Storage 4. You get a call from an administrator who cannot delete a quota entry for a user account. What would you tell the administrator to check? Lesson Summary ■ Use Windows XP Professional disk quotas to allocate disk space usage to users. Windows XP Professional disk quotas track and control disk usage on a per-user, per-volume basis. You can set disk quotas, quota thresholds, and quota limits for all users and for individual users. You can apply disk quotas only to Windows XP Professional NTFS volumes. ■ You can set identical quotas for all users or you can configure different quotas for individual users. ■ You can determine the basic status of the quota management system by looking at the traffic light indicator and the status text display on the Quota tab of a volume’s Properties dialog box. ■ You can monitor disk quotas by using the Quota Entries For dialog box, which you access by clicking Quota Entries on the Quota tab of a volume’s Properties dialog box. ■ There are a number of guidelines you should follow when using disk quotas. The most important guideline is that installing applications can use up disk quotas rap- idly, so you should log on as an administrator without quota limits to install appli- cations. 10-49 Lesson 4: Increasing Security by Using EFS Encryption is the process of making information indecipherable to protect it from unau- thorized viewing or use. A key is required to decode the information. The Encrypting File System (EFS) provides encryption for data in NTFS files stored on disk. This encryp- tion is public key–based and runs as an integrated system service, making it easy to man- age, difficult to attack, and transparent to the file owner. If a user who attempts to access an encrypted NTFS file has the private key to that file (which is assigned when the user logs on), the file can be decrypted so that the user can open the file and work with it transparently as a normal document. A user without the private key is denied access. Windows XP Professional also includes the Cipher command, which provides the capability to encrypt and decrypt files and folders from a command prompt. Windows XP Professional also provides a recovery agent, a specially designated user account that can still recover encrypted files if the owner loses the private key. After this lesson, you will be able to ■ Describe EFS. ■ Encrypt folders and files. ■ Decrypt folders and files. ■ Control encryption from the command line by using the Cipher command. ■ Create an EFS recovery agent. Estimated lesson time: 40 minutes Overview of EFS EFS allows users to encrypt NTFS files by using a strong public key–based crypto- graphic scheme that encrypts all files in a folder. Users with roaming profiles can use the same key with trusted remote systems. No administrative effort is needed to begin, and most operations are transparent. Backups and copies of encrypted files are also encrypted if they are in NTFS volumes. Files remain encrypted if you move or rename them, and temporary files created during editing and left unencrypted in the paging file or in a temporary file do not defeat encryption. You can set policies to recover EFS-encrypted data when necessary. The recovery pol- icy is integrated with overall Windows XP Professional security policy (see Chapter 16, “Configuring Security Settings and Internet Options,” for more on security policy). Con- trol of this policy can be delegated to individuals with recovery authority, and different recovery policies can be configured for different parts of the enterprise. Data recovery discloses only the recovered data, not the key that was used to encrypt the file. Several protections ensure that data recovery is possible and that no data is lost in the case of total system failure. Lesson 4 Increasing Security by Using EFS 10-50 Chapter 10 Managing Data Storage EFS is configured either from Windows Explorer or from the command line. It can be enabled or disabled for a computer, domain, or organizational unit (OU) by resetting recovery policy in the Group Policy console in Microsoft Management Console (MMC). You can use EFS to encrypt and decrypt files on remote file servers but not to encrypt data that is transferred over the network. Windows XP Professional provides network protocols, such as Secure Sockets Layer (SSL) authentication, to encrypt data over the network. Table 10-4 lists the key features provided by Windows XP Professional EFS. Security Alert Even when you encrypt files, an intruder who accesses your computer can access those files if your user account is still logged on to the computer. Be sure to lock your console when you are not using the computer, or configure a screensaver to require a pass- word when the computer is activated. If the computer is configured to go to standby mode when it is idle, you should require a password to bring the computer out of standby. These precautions are particularly important on portable computers, which people are more likely to leave unattended while the user is logged on. Table 10-4 EFS Features Feature Description Transparent encryption In EFS, file encryption does not require the file owner to decrypt and re-encrypt the file on each use. Decryption and encryption happen transparently on file reads and writes to disk. Strong protection of encryption keys Public key encryption resists all but the most sophisticated methods of attack. Therefore, in EFS, the file encryption keys are encrypted by using a public key from the user’s certificate. (Note that Windows XP Professional and Windows 2000 use X.509 v3 certificates.) The list of encrypted file encryption keys is stored with the encrypted file and is unique to it. To decrypt the file encryption keys, the file owner sup- plies a private key, which only he or she has. Integral data-recovery system If the owner’s private key is unavailable, the recovery agent can open the file using his or her own private key. There can be more than one recovery agent, each with a different public key, but at least one pub- lic recovery key must be present on the system to encrypt a file. Secure temporary and paging files Many applications create temporary files while you edit a document, and these temporary files can be left unencrypted on the disk. On computers running Windows XP Professional, EFS can be imple- mented at the folder level, so any temporary copies of an encrypted file are also encrypted, provided that all files are on NTFS volumes. EFS resides in the Windows operating system kernel and uses the nonpaged pool to store file encryption keys, ensuring that they are never copied to the paging file. 10-51 How to Encrypt a Folder The recommended method to encrypt files is to create an encrypted folder and place files in that folder. To encrypt a folder, use these steps: 1. In Windows Explorer, right-click the folder and click Properties. 2. In the Properties dialog box for the folder, on the General tab, click Advanced. 3. In the Advanced Attributes dialog box (refer to Figure 10-14), select the Encrypt Contents To Secure Data check box, and then click OK. 4. Click OK to close the Properties dialog box for the folder. The folder is now marked for encryption, and all files placed in the folder are encrypted. Folders that are marked for encryption are not actually encrypted; only the files within the folder are encrypted. Exam Tip Compressed files cannot be encrypted, and encrypted files cannot be com- pressed with NTFS compression. After you encrypt the folder, when you save a file in that folder, the file is encrypted using file encryption keys, which are fast symmetric keys designed for bulk encryption. The file is encrypted in blocks, with a different file encryption key for each block. All the file encryption keys are stored and encrypted in the Data Decryption field (DDF) and the Data Recovery field (DRF) in the file header. Caution If an administrator removes the password on a user account, the user account will lose all EFS-encrypted files, personal certificates, and stored passwords for Web sites or net- work resources. Each user should make a password reset disk to avoid this situation. To cre- ate a password floppy disk, open User Accounts and, under Related Tasks, click Prevent A Forgotten Password. The Forgotten Password Wizard steps you through creating the password reset disk. How to Decrypt a Folder Decrypting a folder or file refers to clearing the Encrypt Contents To Secure Data check box in a folder’s or file’s Advanced Attributes dialog box, which you access from the folder’s or file’s Properties dialog box. Once decrypted, the file remains decrypted until you select the Encrypt Contents To Secure Data check box. The only reason you might want to decrypt a file is if other people need access to the folder or file—for example, if you want to share the folder or make the file available across the network. ! Lesson 4 Increasing Security by Using EFS 10-52 Chapter 10 Managing Data Storage How to Control Encryption From the Command Line by Using the Cipher Command The Cipher command provides the capability to encrypt and decrypt files and folders from a command prompt. The following example shows the available switches for the Cipher command, which are described in Table 10-5: cipher [/e | /d] [/s:folder_name] [/a] [/i] [/f] [/q] [/h] [/k] [file_name [ ]] If you run the Cipher command without parameters, it displays the encryption state of the current folder and any files that it contains. You can specify multiple file names and use wildcards. You must put spaces between multiple parameters. How to Create an EFS Recovery Agent If you lose your file encryption certificate and associated private key through disk fail- ure or for any other reason, a user account designated as the recovery agent can open the file using his or her own certificate and associated private key. If the recovery agent is on another computer in the network, send the file to the recovery agent. Table 10-5 Cipher Command Switches Switch Description /e Encrypts the specified folders. Folders are marked so any files that are added later are encrypted. /d Decrypts the specified folders. Folders are marked so any files that are added later are not encrypted. /s Performs the specified operation on files in the given folder and all subfolders. /a Performs the specified operation on files as well as folders. Encrypted files could be decrypted when modified if the parent folder is not encrypted. Encrypt the file and the parent folder to avoid problems. /i Continues performing the specified operation even after errors have occurred. By default, Cipher stops when an error is encountered. /f Forces the encryption operation on all specified files, even those that are already encrypted. Files that are already encrypted are skipped by default. /q Reports only the most essential information. /h Displays files with the hidden or system attributes, which are not shown by default. /k Creates a new file encryption key for the user running the Cipher command. Using this option causes the Cipher command to ignore all other options. file_name Specifies a pattern, file, or folder. 10-53 Security Alert The recovery agent can bring his or her private key to the owner’s computer, but it is never a good security practice to copy a private key onto another computer. It is a good security practice to rotate recovery agents. However, if the agent designa- tion changes, access to the file is denied. For this reason, you should keep recovery certificates and private keys until all files that are encrypted with them have been updated. The person designated as the recovery agent has a special certificate and associated private key that allow data recovery. To recover an encrypted file, the recovery agent does the following: ■ Uses Backup or another backup tool to restore a user’s backup version of the encrypted file or folder to the computer where his or her file recovery certificate is located. ■ In Windows Explorer, opens the Properties dialog box for the file or folder, and in the General tab, clicks Advanced. ■ Clears the Encrypt Contents To Secure Data check box. ■ Makes a backup version of the decrypted file or folder and returns the backup ver- sion to the user. Practice: Increasing Security by Using EFS In this practice, you log on as an administrator and encrypt a folder and its files. You then log on using a different user account, and attempt to open an encrypted file and disable encryption on the encrypted file. 1. In Windows Explorer, create a folder named Secret on the C drive. 2. In the Secret folder, create a text file named SecretFile.txt. 3. Right-click the Secret folder, and then click Properties. Windows XP Professional displays the Secret Properties dialog box with the Gen- eral tab active. 4. Click Advanced. The Advanced Attributes dialog box appears. 5. Select the Encrypt Contents To Secure Data check box, and then click OK. 6. Click OK to close the Secret Properties dialog box. The Confirm Attribute Change dialog box informs you that you are about to encrypt a folder. You have two choices: You can encrypt only this folder, or you can encrypt the folder and all subfolders and files in the folder. Lesson 4 Increasing Security by Using EFS 10-54 Chapter 10 Managing Data Storage 7. Select the Apply Changes To This Folder, Subfolders And Files option, and then click OK. 8. Open the Secret folder. 9. What color is the SecretFile.txt text file? Why? 10. In the Secret folder, right-click the SecretFile.txt text file, and then click Properties. The SecretFile.txt Properties dialog box appears. 11. Click Advanced. The Advanced Attributes dialog box appears. Notice that the Encrypt Contents To Secure Data check box is selected. 12. Close the Advanced Attributes dialog box. 13. Close the Properties dialog box. 14. Close all windows and log off. 15. Log on as User5. 16. In Windows Explorer, locate and open the SecretFile.txt text file. 17. What happens? 18. Close Notepad. 19. Right-click the SecretFile.txt text file, and then click Properties. 20. Click Advanced. 21. Clear the Encrypt Contents To Secure Data check box, and then click OK. 22. Click OK to close the SecretFile.txt Properties dialog box. The Error Applying Attributes dialog box appears and informs you that access to the file is denied. 23. Click Cancel. 24. Close all open windows and dialog boxes. 25. Log off. Lesson Review Use the following questions to help determine whether you have learned enough to move on to the next lesson. If you have difficulty answering these questions, review [...]... line using the Cipher command ■ Windows XP Professional also provides a recovery agent If an owner loses the private key, the recovery agent can still recover the encrypted file Lesson 5 Maintaining Disks with Disk Defragmenter, Check Disk, and Disk Cleanup 10 -57 Lesson 5: Maintaining Disks with Disk Defragmenter, Check Disk, and Disk Cleanup Windows XP Professional saves files and folders in the... Cleanup For dialog box (see Figure 10- 25) The available options are explained in Table 10-10 F10us 25 Figure 10- 25 tures Use the More Options tab of the Disk Cleanup For dialog box to access additional fea- Lesson 5 Table 10-10 Maintaining Disks with Disk Defragmenter, Check Disk, and Disk Cleanup 10- 65 Additional Features on the Disk Cleanup More Options Tab Option Description Windows Components Click...Lesson 4 Increasing Security by Using EFS 10 -55 the material in this lesson before beginning the next lesson You can find answers to these questions in the “Questions and Answers” section at the end of this chapter 1 What is encryption and what is the EFS? 2 Which of the following files and folders does Windows XP Professional allow you to encrypt? (Choose all that apply.) a A file... the defragmented volume Additionally, you can view a report showing files that could not be defragmented Lesson 5 Maintaining Disks with Disk Defragmenter, Check Disk, and Disk Cleanup 10 -59 Figure 10-22 shows the Disk Defragmenter dialog box after you have analyzed the C drive Windows XP Professional displays another Disk Defragmenter dialog box, indicating that you need to defragment the volume You... encrypted? 4 If the private key belonging to the owner of an encrypted file is not available, how can you decrypt the file? 5 By default, the recovery agent for a computer running Windows XP Professional in a workgroup is , and the recovery agent for a computer running Windows XP Professional in a domain environment is _ Lesson Summary ■ EFS allows users to encrypt files and folder on an... click Analyze 3 If Windows XP Professional displays a dialog box, indicating that there is no need to defragment your volume at this time, click Close, and then read through Steps 6 through 12 10-66 Chapter 10 Managing Data Storage 4 If Windows XP Professional displays a Disk Defragmenter dialog box, indicating that you need to defragment your volume now, click View Report 5 In the Analysis Report dialog... running Windows XP Professional just as you would if it were a laptop computer running Windows XP Professional so that you can use offline folders and files Exercise 1: Configure Offline Folders and Files 1 Log on with a user account that is a member of the Administrators group 2 Click Start, right-click My Computer, and then click Open 3 On the Tools menu, click Folder Options Windows XP Professional displays... Folder Options, and then click the Offline Files tab Go to Step 5 5 Select the Enable Offline Files check box 6 Ensure that the Synchronize All Offline Files Before Logging Off check box is selected, and then click OK Your computer is now configured so that you can use offline folders and files Lesson 6 Configuring Offline Folders and Files 10- 75 7 Close the My Computer window Exercise 2: Configure Offline... Windows XP Professional provides two types of compression: Compressed Folders and NTFS compression A compressed folder appears in Windows Explorer as an icon of a zipper across a folder NTFS compression is a function of the NTFS file system that allows you to compress files, folders, or an entire volume ■ Use Windows XP Professional disk quotas to allocate disk space usage to users Windows XP Professional... Note If you started with a clean hard disk and installed Windows XP Professional in Chapter 2, these disk maintenance tools will probably not find much to clean up or repair Exercise 1: Defragment a Hard Drive 1 Click Start, point to All Programs, point to Accessories, point to System Tools, and then click Disk Defragmenter Windows XP Professional displays the Disk Defragmenter dialog box 2 If there . close it. 15. Copy the i386 folder from your CD-ROM to the User5 folder. Windows XP Professional begins copying files from the i386 folder on the CD- ROM to a new i386 folder in the User5 folder. box. 10. Log off. 11. Log on as User5. 12. Start Windows Explorer and create a User5 folder on drive C. 13. Insert the CD-ROM you used to install Windows XP Professional into your CD- ROM drive. 14 Users dialog box. 4. In the Name text box, type User5, and then click OK. Windows XP Professional displays the Add New Quota Entry dialog box. 5. Click Limit Disk Space To. What are the default