XK0-006 Exam Dumps - CompTIA Linux+ Questions and Answers

This scenario involves Linux file attributes and falls under the System Management domain of the CompTIA Linux+ V8 objectives. Although the administrator is operating as the root user, the system prevents the file from being modified. This behavior indicates that standard UNIX permissions are not the root cause of the problem.

The critical clue is provided by the lsattr /etc/resolv.conf output, which shows the immutable (i) attribute set on the file. When a file is marked immutable, it cannot be modified, deleted, renamed, or written to by any user, including root. This restriction overrides normal file permissions and ownership settings.

The chattr command is used to modify extended file attributes on Linux filesystems such as ext4. The option -i specifically removes the immutable attribute, restoring the file’s ability to be edited. Therefore, running chattr -i /etc/resolv.conf allows the administrator to open and modify the file successfully.

The other options do not resolve the issue. chown root changes file ownership, but the file is already owned by root. chmod 750 modifies permission bits, but permissions are ignored when the immutable attribute is set. chgrp root changes the group ownership, which also has no effect when immutability is enforced.

Linux+ V8 documentation highlights immutable files as a security and stability feature, commonly used to protect critical configuration files from accidental or unauthorized changes. Administrators must explicitly remove this attribute before making modifications.

Therefore, the correct command to allow editing the file is B. chattr -i /etc/resolv.conf.

Service management using systemd is a core Linux+ V8 system management objective. Administrators frequently need to view the current status of all services to determine which ones are running, stopped, failed, or inactive.

The correct command is systemctl list-units --type=services, which displays all loaded service units along with their current state, including whether they are active, inactive, failed, or running. This provides a comprehensive, real-time view of service statuses on the system and is commonly used during troubleshooting and audits.

Option A, systemctl is-active, is designed to check the status of a single service, not all services. Option B lists socket units, not services. Option C, systemctl is-enabled, checks whether services are enabled at boot, not whether they are currently running.

Linux+ V8 documentation explicitly references systemctl list-units --type=service as the primary command for viewing service runtime states. Therefore, the correct answer is D.

Password policy enforcement is a critical component of system security covered in the CompTIA Linux+ V8 objectives. One common control implemented in Linux systems is restricting how frequently users can change their passwords, often referred to as minimum password age enforcement.

The primary reason multiple password changes within a short time frame are not allowed is to prevent password cycling attacks. Without this restriction, a user could repeatedly change their password in quick succession to bypass password history controls and eventually reuse a previously compromised or weak password. Option C accurately describes this scenario and aligns directly with Linux+ V8 security guidance.

Linux systems enforce this behavior through tools such as chage and PAM (Pluggable Authentication Modules). Administrators can configure minimum password age values to ensure users must wait a defined period before changing passwords again. This ensures that password history requirements are effective and meaningful.

The other options are incorrect. Option A confuses password expiration with brute-force mitigation, which is typically addressed through account lockout policies. Option B refers to password complexity, which is enforced through character requirements rather than change frequency. Option D is unrelated, as password expiration policies do not enforce multifactor authentication.

Linux+ V8 documentation emphasizes layered access controls, and preventing password reuse through enforced timing restrictions is a core principle of secure authentication design.

Therefore, the correct answer is C.

Comprehensive and Detailed Explanation From Exact Extract:

To temporarily configure a Linux virtual machine as a router, the technician must enable IP forwarding and set up iptables rules to allow and masquerade traffic:

A. echo "1" > /proc/sys/net/ipv4/ip_forward: Enables IPv4 forwarding in the Linux kernel, allowing the VM to forward packets between interfaces.

B. iptables -A FORWARD -j ACCEPT: Adds a rule to the iptables firewall to accept all forwarded packets (allows traffic to be routed).

G. iptables -t nat -s 10.10.204.0/24 -A POSTROUTING -j MASQUERADE: Sets up network address translation (NAT) for outgoing packets from the 10.10.204.0/24 subnet, masquerading them as if they are coming from the VM’s external IP.

Other options:

C. and H. are not relevant for routing/NAT in this context (PREROUTING is generally used for DNAT, not for standard source NAT).

D. is syntactically incorrect and mixes PREROUTING with MASQUERADE, which is not the proper combination for SNAT.

E. disables forwarding.

F. is not related to IP forwarding.

Comprehensive and Detailed 250 to 350 words of Explanation From Linux+ V8 documents:

Password complexity is a fundamental concept within the Security domain of CompTIA Linux+ V8. Complex passwords significantly reduce the risk of successful brute-force, dictionary, and credential-stuffing attacks. Linux+ emphasizes evaluating passwords based on length, character variety, unpredictability, and resistance to common word patterns.

Option C, H3s@1dSh3t0|d, is the most complex password among the choices. It demonstrates strong security characteristics by incorporating:

Uppercase letters (H, S)

Lowercase letters (s, d, t)

Numbers (3, 1, 0)

Multiple special characters (@, |)

A longer overall length compared to some other options

Additionally, option C uses character substitution (leet-style) in a way that breaks up recognizable words more effectively than the other choices. This significantly increases entropy and makes the password harder to guess using rule-based or hybrid cracking techniques.

Option A includes uppercase letters and numbers but lacks special characters and is relatively short. Option B includes special characters and mixed case, but it still closely resembles readable words, making it more susceptible to dictionary-based attacks. Option D uses only alphabetic characters and clear word patterns, making it the weakest choice.

Linux+ V8 documentation highlights that the strongest passwords combine length with diverse character classes and minimal predictability. Password C best meets all of these criteria and would score highest against common password-cracking strategies.

Therefore, the correct answer is C. H3s@1dSh3t0|d.

This scenario involves firewall configuration and service accessibility, which falls under the Security domain of the CompTIA Linux+ V8 objectives. The key to resolving this issue is interpreting both the firewall output and the web server status correctly.

The web server output shows that the service is actively listening on TCP port 443, which is the standard port for HTTPS (secure web traffic). The line tcp LISTEN 0 4096 *:443 *:* confirms that the web server is running properly and is ready to accept incoming connections on port 443 from any interface. This indicates that the problem is not with the web server configuration itself.

However, the firewall output clearly shows that incoming connections to port 443 are being blocked. The rules 443/tcp DENY Anywhere and 443/tcp (v6) DENY Anywhere (v6) indicate that the Uncomplicated Firewall (UFW) is explicitly denying HTTPS traffic for both IPv4 and IPv6. As a result, external clients cannot establish a secure connection to the server, even though the service is running correctly.

To resolve this issue securely and correctly, the administrator must remove the firewall rule that denies HTTPS traffic. Option C, ufw delete deny https/tcp, directly removes the blocking rule while preserving the rest of the firewall configuration. This aligns with Linux+ best practices, which emphasize making precise firewall changes rather than disabling security controls entirely.

The other options are incorrect. Option A, ufw disable, would completely turn off the firewall, creating a significant security risk. Option B, ufw allow 80/tcp, only opens HTTP traffic on port 80 and does not resolve HTTPS connectivity issues. Option D, ufw allow 4096/tcp, incorrectly attempts to open an internal socket backlog value rather than a valid service port.

Therefore, the correct and most secure solution is C.