XK0-005 Online Practice Questions and Answers

Correct Answer: B

Explanation: The command mv .ssh/authorized_key .ssh/authorized_keys will resolve the issue and allow an SSH connection to be established without a password. The issue is caused by the incorrect file name of the authorized key file on the server. The file should be named authorized_keys, not authorized_key. The mv command will rename the file and fix the issue. The other options are incorrect because they either do not affect the file name (restorecon or chmod) or do not restart the SSH service (systemct1). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter

13: Managing Network Services, page 410.

Correct Answer: A

Explanation: The mount /dev/sdb1 /media/usb command will mount the USB drive to /media/usb. This command will attach the filesystem on the first partition of the USB drive (/dev/sdb1) to the mount point /media/usb, making it accessible to

the system. The mount /dev/sdb0 /media/usb command is invalid, as there is no such device as /dev/sdb0. The mount /dev/sdb /media/usb command is incorrect, as it will try to mount the entire USB drive instead of its partition, which may

cause errors or data loss. The mount -t usb /dev/sdb1 /media/usb command is incorrect, as usb is not a valid filesystem type for mount. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 14:

Managing Disk Storage, page 455.

Correct Answer: D

Explanation: The command iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT -- to-destination 192.0.2.25:3128 adds a rule to the nat table that redirects all incoming TCP packets with destination port 80 (HTTP) to the proxy server

192.0.2.25 on port 3128. This is the correct way to achieve the task. The other options are incorrect because they either delete a rule (-D), use the wrong protocol (top instead of tcp), or use the wrong port (81 instead of 80). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, page 381.

Correct Answer: B

The ifcfg command is used to configure network interfaces on Linux systems. The -a option displays information about all network interfaces, including their IP addresses, netmasks, gateways, and other parameters. This command can help the administrator obtain the network information from the statically assigned workstations before they are reconnected to the network. References: [Linux Networking: ifcfg Command With Examples]

Correct Answer: C

Explanation: The command ls | cpio -ov > cloud.cpio can help to create a new cloud.cpio archive containing all the files from the current directory. The ls command lists the files in the current directory and outputs them to the standard output.

The | operator pipes the output to the next command. The cpio command is a tool for creating and extracting compressed archives. The -o option creates a new archive and the -v option shows the verbose output. The > operator redirects the

output to the cloud.cpio file. This command will create a new cloud.cpio archive with all the files from the current directory. The other options are incorrect because they either use the wrong options (-i instead of -o), the wrong arguments

(cloud.epio instead of cloud.cpio), or the wrong syntax (< instead of > or missing |). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 11:

Managing Files and Directories, page 351.

Correct Answer: D

Explanation: The command ip route add 10.0.213.5/32 via 10.0.5.1 dev eth0 adds a static route to the routing table that sends packets destined for 10.0.213.5/32 (a single host) through the gateway 10.0.5.1 on the interface eth0. This is the correct way to achieve the goal. The other options are incorrect because they either use the wrong syntax (route -i etho -p add), the wrong command (route modify), or the wrong file (/proc/net/route). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, page 379.

Correct Answer: A

To mirror the website files on the primary web server, www1, to the backup web server, www2, the administrator can use the command rsync -a -e ssh /var/www/html/ user1@www2:/var/www/html (A). This will synchronize all files and directories under /var/www/html/ on www1 to /var/www/html on www2 using ssh as the remote shell. The -a option will preserve all attributes and permissions of the files. The other commands will not mirror the website files, but either copy them once, download them from a web server, or archive them. References: [CompTIA Linux+ Study Guide], Chapter 12: Troubleshooting Linux Systems, Section: Synchronizing Files with rsync [How to Use rsync Command in Linux]

Correct Answer: CD

The httpd.service is the Apache HTTPD Server, which is a web service that runs on Linux systems. The output 1 shows that the httpd.service is inactive (dead), which means that it is not running. The output 1 also shows that the httpd.service is disabled, which means that it is not enabled to auto start at boot time. Therefore, the statements C and D best describe the root cause of the issue. The statements A, B, E, and F are incorrect because they do not match the output 1. References: [How to Manage Systemd Services on a Linux System]

Correct Answer: A

Explanation: The command chmod 755 filename.log should be used to set filename.log permissions to -rwxr--r--. The chmod command is a tool for changing file permissions on Linux file systems. The permissions can be specified in octal notation, where each digit represents the permissions for the owner, group, and others respectively. The permissions are encoded as follows:

0: no permission

1: execute permission

2: write permission

4: read permission

5: read and execute permissions (4 + 1)

6: read and write permissions (4 + 2)

7: read, write, and execute permissions (4 + 2 + 1) The command chmod 755 filename.log will set the permissions to -rwxr--r--, which means that the owner has read, write, and execute permissions (7), the group has read and execute permissions (5), and others have read and execute permissions (5). This is the correct command to use to accomplish the task. The other options are incorrect because they either set the wrong permissions (chmod 640, chmod 740, or chmod 744) or do not exist (chmod -G). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 11: Managing Files and Directories, page 345.

Correct Answer: D

This command will use the chsh tool to change the login shell of the users www-data and db to /bin/false, which means they will not be able to log in to the system1. This will prevent unauthorized access attempts and improve security. References: 1: Replacing /bin/bash with /bin/false in /etc/passwd file