XK0-006 Practice Test 33 — 15 Questions

Question 1

Refer to the exhibit. A user cannot access a web server, but another host on the same subnet can. What is the most likely cause?

Accepted Answer

The user's workstation has a local firewall blocking outbound HTTPS.

Answer

The network router is blocking the user's traffic.

Answer

The web server is down.

Answer

DNS is resolving to the wrong IP for the user.

Question 2

A system administrator is troubleshooting a network issue on a Linux server running CentOS 7. The server is unable to connect to the internet, but internal network connections work fine. The administrator checks the network configuration: the server has a static IP 192.168.1.100/24, default gateway 192.168.1.1, and DNS server 8.8.8.8. The administrator can ping the gateway but cannot ping 8.8.8.8. From the server, a traceroute to 8.8.8.8 stops at the gateway. The administrator also notices that the route table shows a default route via 192.168.1.1. What is the most likely cause?

Accepted Answer

The router is not performing NAT correctly. The server can ping the gateway (192.168.1.1) but cannot reach 8.8.8.8, and traceroute stops at the gateway. This indicates that the server’s default route is correctly configured and the gateway is reachable, but the router is not forwarding traffic beyond the local subnet. Since internal connections work, the most likely cause is that the router is not performing Network Address Translation (NAT) correctly, which is required to translate private IP addresses (192.168.x.x) to a public IP for internet access.

Answer

The DNS server is not responding

Answer

The default gateway is not reachable

Answer

The subnet mask is incorrectly configured

Question 3

A DevOps team uses Git for version control of Ansible playbooks. They notice that a recent commit introduced errors in the playbook. Which Git command sequence should they use to temporarily revert to a previous commit while preserving the faulty commit in history?

Accepted Answer

git revert HEAD. The `git revert HEAD` command creates a new commit that undoes the changes introduced by the most recent commit, effectively reverting the playbook to its previous state while preserving the faulty commit in the project history. This is the correct approach for a team using shared repositories because it maintains a linear, non-destructive history that can be safely pushed to a remote without force-pushing.

Answer

git checkout HEAD~1

Answer

git reset --hard HEAD~1

Answer

git branch -d faulty-branch

Question 4

A systemd timer unit is configured to run a service every hour but the service never executes. The timer shows as active and enabled. Which of the following is the most likely cause?

Accepted Answer

The service unit is masked. When a systemd timer unit is active and enabled but the associated service never executes, the most likely cause is that the service unit is masked. A masked unit is symlinked to /dev/null, which prevents systemd from starting it regardless of timer triggers. The timer itself runs correctly, but systemd silently ignores the request to activate the masked service.

Answer

The timer is not started

Answer

The service unit is not enabled

Answer

The timer unit has a mistake in the OnCalendar directive

Question 5

A service named 'myapp' is currently running but should be disabled so it does not start automatically at boot. Which command accomplishes this?

Accepted Answer

systemctl disable myapp. The correct command is `systemctl disable myapp` because it removes the symlinks that cause the service to start automatically at boot, while leaving the currently running service unaffected. This directly meets the requirement of disabling automatic startup without stopping the running process.

Answer

systemctl kill myapp

Answer

systemctl mask myapp

Answer

systemctl stop myapp

Question 6

A security team requires that all scripts run from a specific directory must be signed with a GPG key before execution. Which Linux feature can enforce this policy?

Accepted Answer

IMA/EVM with fs-verity. IMA/EVM (Integrity Measurement Architecture / Extended Verification Module) with fs-verity is the correct choice because it provides file-level integrity enforcement by requiring a valid GPG signature on scripts before execution. fs-verity enables per-file Merkle tree verification, and IMA can be configured to measure and enforce signatures, ensuring only signed scripts from the specified directory are allowed to run.

Answer

setuid bit

Answer

dm-verity

Answer

SELinux boolean

Question 7

A system fails to boot after installing a new SATA disk. The BIOS recognizes the disk. What is the most likely cause?

Accepted Answer

Boot order is incorrect. The most likely cause is an incorrect boot order because the BIOS recognizes the new SATA disk but the system still fails to boot. When a new disk is installed, the BIOS may default to booting from it if it appears earlier in the boot sequence than the original boot device, and if the new disk lacks a bootable operating system, the system will hang or fail to boot. This is a common scenario where the BIOS sees the disk but the boot priority is misconfigured, not a corruption of GRUB or a lack of formatting/partitioning.

Answer

GRUB configuration is corrupted

Answer

The new disk is not formatted

Answer

The new disk is not partitioned

Question 8

A Linux server is not accepting SSH connections. The administrator wants to troubleshoot the issue. Which THREE actions should be taken?

Accepted Answer

Check /etc/ssh/sshd_config for configuration errors. B is correct because /etc/ssh/sshd_config is the primary configuration file for the OpenSSH server. Syntax errors, incorrect directives (e.g., PermitRootLogin no, Port 22 commented out), or misconfigured authentication settings can prevent SSH from accepting connections. Checking this file is a fundamental step in troubleshooting SSH issues.

Answer

Reboot the server

Answer

Reinstall the SSH package (apt reinstall openssh-server)

Question 9

A system administrator wants to automate server configuration and management across multiple Linux hosts. Which TWO tools are configuration management solutions designed for this purpose? (Choose two.)

Accepted Answer

Puppet. Puppet is a mature configuration management tool that uses a declarative language (Puppet DSL) to define desired system states and enforces them via a client-server (agent-master) architecture over HTTPS. It automates server configuration across multiple hosts by applying manifests that specify packages, services, files, and users, ensuring consistency without manual intervention.

Answer

Docker

Answer

Nagios

Answer

Kubernetes

Question 10

Which TWO commands are used to view a file page by page?

Accepted Answer

more. The `more` and `less` commands are both pager utilities that display file contents one screen at a time, allowing the user to scroll forward (and in the case of `less`, backward) through the output. `more` is the traditional pager that pauses after each screenful, while `less` is a more feature-rich pager that supports backward navigation and searching. Both are correct for viewing a file page by page.

Answer

tail

Answer

cat

Answer

head

Question 11

A Linux service fails to start. Which command should the administrator use to examine recent system logs for error messages related to the service?

Accepted Answer

journalctl -xe. The `journalctl -xe` command is correct because it displays the systemd journal with the `-x` flag adding explanatory context to log entries and the `-e` flag jumping to the end of the log, showing the most recent messages. This is the standard way to examine recent system logs for error messages related to a failing service in a systemd-based Linux distribution.

Answer

systemctl list-units

Answer

tail -f /var/log/messages

Answer

dmesg -T

Question 12

A DevOps team wants to automatically run tests before every commit in a local Git repository. Which Git hook should be used?

Accepted Answer

pre-commit. The pre-commit hook runs before a commit is created, making it the correct choice for automatically running tests before every commit in a local Git repository. This hook can validate code quality, run unit tests, or check for syntax errors, and if it exits with a non-zero status, the commit is aborted.

Answer

post-receive

Answer

post-commit

Answer

pre-push

Question 13

Which two of the following are valid methods to pass environment variables to a Docker container at runtime? (Select TWO.)

Accepted Answer

Defining variables in a .env file and using --env-file. The `--env-file` flag in `docker run` allows you to pass environment variables from a file (typically a `.env` file) to the container at runtime. This method is useful for managing multiple variables without cluttering the command line and supports variable substitution and quoting rules as defined by Docker.

Answer

Using the ENV instruction in the Dockerfile

Answer

Using the export command inside the container

Answer

Using the ARG instruction in the Dockerfile

Question 14

A Linux server is experiencing slow boot times. The administrator wants to identify which systemd services are taking the longest to start. Which command should be used?

Accepted Answer

systemd-analyze blame. The `systemd-analyze blame` command prints a list of all running systemd units, sorted by the time they took to initialize during boot. This directly answers the administrator's need to identify which services are causing slow boot times by showing the exact startup duration for each unit.

Answer

systemd-analyze time

Answer

journalctl -b -p 3

Answer

systemctl list-units --all

Question 15

A system is running out of disk space in the /var/log directory. The administrator needs to temporarily free up space while preserving the latest log entries. Which approach is best?

Accepted Answer

Run logrotate with compression enabled. Logrotate with compression is the best approach because it rotates, compresses, and optionally removes old log files while preserving the latest entries. It can be configured to keep a specific number of rotated logs, thus freeing disk space without deleting current logs. This matches the requirement to temporarily free up space while retaining the most recent log data.

Answer

find /var/log -mtime +7 -delete

Answer

cat /dev/null > /var/log/messages

Answer

rm -rf /var/log/*