CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 261:

  A Linux administrator receives a ticket stating that end users are unable to access the company's internal cloud server. The administrator executes the following command:

  ping usl.com

  Result:

  ping: cannot resolve usl.com: Unknown Host

  Which of the following files needs to be modified to allow end users to access usl.com?

  A. /etc/resolv.conf
  B. /etc/interfaces
  C. /etc/hosts.allow
  D. /etc/hostname
  A. /etc/resolv.conf

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  Explanation

• Question 262:

  To harden one of the servers, an administrator needs to remove the possibility of remote administrative login via the SSH service. Which of the following should the administrator do?

  A. Add the line DenyUsers root to the /etc/hosts.deny file.
  B. Set PermitRootLogin to no in the /etc/ssh/sshd_config file.
  C. Add the line account required pam_nologin. so to the /etc/pam.d/sshd file.
  D. Set PubKeyAuthentication to no in the /etc/ssh/ssh_config file.
  B. Set PermitRootLogin to no in the /etc/ssh/sshd_config file.

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  Explanation

  The administrator should set PermitRootLogin to no in the /etc/ssh/sshd_config file to remove the possibility of remote administrative login via the SSH service. The PermitRootLogin directive controls whether the root user can log in using SSH. Setting it to no will deny any remote login attempts by the root user. This will harden the server and prevent unauthorized access. The administrator should also restart the sshd service after making the change. The other options are incorrect because they either do not affect the SSH service (/etc/hosts.deny or /etc/pam.d/sshd) or do not prevent remote administrative login (PubKeyAuthentication).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 13: Managing Network Services, page 413.

• Question 263:

  An administrator logs in to a Linux server and notices the clock is 37 minutes fast. Which of the following commands will fix the issue?

  A. hwclock
  B. ntpdate
  C. timedatectl
  D. ntpd -q
  B. ntpdate

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  Explanation

• Question 264:

  A systems administrator receives the following errors via email from the system log: go XFS (loop0): Metadata CRC error detected at xfs_agi_read_verify+0xcb/0xfe XFS (loop0): First 128 bytes of corrupted metadata buffer XFS (loop0): metadata I/O error in "xfs_trans_read_buf_map" at daddr 0x2 len 1 error 74 A few minutes later, the administrator starts receiving reports that some of the images in the company's website are not loading properly. The systems administrator runs some commands and receives the following outputs: css

  Output 1

  NAME FSTYPE UUID MOUNTPOINT

  sda ext4 02ae47-fe457-45bc /

  sdb xfs 347c7056 /var/www/html

  Output 2

  DocumentRoot "/var/www/html"

  Output 3

  httpd.service - The Apache HTTP Server

  Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)

  Active: active (running) since Sun 1991-05-24 16:12:43 UTC; 30y ago

  Main PID: 252 (httpd)

  Which of the following would be the appropriate steps to take to solve this issue?

  A. systemctl stop httpd umount /dev/sdb1 xfs_repair /dev/sdb1 mount /dev/sdb1 /var/www/html systemctl start httpd
  B. umount /dev/sdb1 xfs_repair /dev/sdb1 xfs_metadump /dev/sdb1 mount /dev/sdb1 /var/www/html systemctl restart httpd
  C. umount /dev/sdb1 systemctl stop httpd xfs_metadump /dev/sdb1 mount /dev/sdb1 /var/www/html systemctl start httpd
  D. systemctl stop httpd xfs_check -L /dev/sdb umount /var/www/html systemctl start httpd
  A. systemctl stop httpd umount /dev/sdb1 xfs_repair /dev/sdb1 mount /dev/sdb1 /var/www/html systemctl start httpd

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  Explanation

  The error is related to XFS filesystem corruption on /dev/sdb1, where the website's images are stored. By stopping the Apache service, unmounting the filesystem, running xfs_repair, and remounting, the filesystem can be repaired, and the service can be restarted safely.

• Question 265:

  A systems administrator is customizing a new Linux server. Which of the following settings for umask would ensure that new files have the default permissions of -rw-r--r--?

  A. 0017
  B. 0027
  C. 0038
  D. 0640
  B. 0027

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  Explanation

  The umask determines the default permission for new files. To get -rw-r--r-- (644), the umask should be set to 0027. This sets the permissions to allow read and write for the owner, read-only for the group, and no permissions for others.

• Question 266:

  The development team wants to prevent a file from being modified by all users in a Linux system, including the root account. Which of the following commands can be used to accomplish this objective?

  A. chmod / app/conf/file
  B. setenforce / app/ conf/ file
  C. chattr +i /app/conf/file
  D. chmod 0000 /app/conf/file
  C. chattr +i /app/conf/file

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  Explanation

  The chattr command is used to change file attributes on Linux systems that support extended attributes, such as ext2, ext3, ext4, btrfs, xfs, and others. File attributes are flags that modify the behavior of files and directories. To prevent a file from being modified by all users in a Linux system, including the root account, the development team can use the chattr +i /app/conf/file command. This command will set the immutable attribute (+i) on the file /app/conf/file, which means that the file cannot be deleted, renamed, linked, appended, or written to by any user or process. To remove the immutable attribute, the development team can use the chattr -i /app/conf/file command. The statement C is correct. The statements A, B, and D are incorrect because they do not prevent the file from being modified by all users. The chmod /app/conf/file command does not work because it requires an argument to specify the permissions to change. The setenforce /app/ conf/file command does not work because it is used to change the SELinux mode, not file attributes. The chmod 0000 /app/conf/file command will remove all permissions from the file, but it can still be modified by the root account.

  References: [How to Use chattr Command in Linux]

• Question 267:

  A Linux administrator needs to deploy an Apache web server in a container. In addition, the container needs to run in the background, and the web server needs to be exposed on port 8080 of the host machine. Which of the following commands will satisfy these requirements?

  A. sudo docker run -b -t -p 8080:80 --name mywebserver httpd
  B. sudo docker run -d -t -p 8080:80 --name myweb httpd
  C. sudo docker run -d -t -p 80:8080 --name myweb httpd
  D. sudo docker run -b -t -p 80:8080 --name mywebserver httpd
  B. sudo docker run -d -t -p 8080:80 --name myweb httpd

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  Explanation

• Question 268:

  A Linux system is failing to boot with the following error:

  

  Which of the following actions will resolve this issue? (Choose two.)

  A. Execute grub-install --root-directory=/mnt and reboot.
  B. Execute grub-install /dev/sdX and reboot.
  C. Interrupt the boot process in the GRUB menu and add rescue to the kernel line.
  D. Fix the partition modifying /etc/default/grub and reboot.
  E. Interrupt the boot process in the GRUB menu and add single to the kernel line.
  F. Boot the system on a LiveCD/ISO.
  B. Execute grub-install /dev/sdX and reboot.
  F. Boot the system on a LiveCD/ISO.

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  Explanation

  The administrator should do the following two actions to resolve the issue:

  Boot the system on a LiveCD/ISO. This is necessary to access the system and repair the boot loader. A LiveCD/ISO is a bootable media that contains a Linux distribution that can run without installation. The administrator can boot the system from the LiveCD/ISO and mount the root partition of the system to a temporary directory, such as /mnt.

  Execute grub-install /dev/sdX and reboot. This will reinstall the GRUB boot loader to the disk device, where sdX is the device name of the disk, such as sda or sdb. The GRUB boot loader is a program that runs when the system is powered on and allows the user to choose which operating system or kernel to boot. The issue is caused by a corrupted or missing GRUB boot loader, which prevents the system from booting. The command grub-install will restore the GRUB boot loader and fix the issue.

  The other options are incorrect because they either do not fix the boot loader (interrupt the boot process in the GRUB menu or fix the partition modifying /etc/default/grub) or do not use the correct syntax (grub-install --root-directory=/mnt instead of grub-install /dev/sdX or rescue or single instead of recovery in the GRUB menu).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 8:

  Managing the Linux Boot Process, pages 265-266.

• Question 269:

  A Linux administrator needs to obtain a list of all volumes that are part of a volume group. Which of the following commands should the administrator use to accomplish this task?

  A. vgs
  B. lvs
  C. fdisk -1
  D. pvs
  B. lvs

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  Explanation

  The lvs command can be used to obtain a list of all volumes that are part of a volume group. This command will display information such as the name, size, attributes, and volume group of each logical volume in the system. The vgs command can be used to obtain a list of all volume groups in the system, not the volumes. The fdisk -1 command is invalid, as -1 is not a valid option for fdisk. The pvs command can be used to obtain a list of all physical volumes in the system, not the volumes.

  References: CompTIA Linux+ (XK0- 005) Certification Study Guide, Chapter 14: Managing Disk Storage, page 461.

• Question 270:

  A systems administrator needs to know the mail exchange (MX) record for the foo.com domain. Which of the following commands will accomplish this task?

  A. telnet mx foo.com
  B. dig mx foo.com
  C. nslookup mx foo.com
  D. host mx foo.com
  B. dig mx foo.com

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  Explanation

  The dig command is used for querying DNS information. To retrieve the MX records for a domain (which indicate where emails should be routed), the command dig mx foo.com is used. This returns the mail servers associated with the domain, including their priority levels.