XK0-005 Exam Dumps - CompTIA Linux+ Questions and Answers

The command systemct1 status systemd-resolved.service will show the information about the service systemd-resolved.service. The systemct1 command is a tool for managing system services and units. The status option displays the current status of a unit, such as active, inactive, or failed. The output also shows the unit description, loaded configuration, process ID, memory usage, and recent log messages. This command will show if the service systemd-resolved.service is running without any errors. This is the correct command to use to accomplish the task. The other options are incorrect because they either perform different actions (enable, mask, or show) or do not show the status of the service (systemct1 show systemd-resolved.service only shows the properties of the service, not the status). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 14: Managing Processes and Scheduling Tasks, page 427.

The administrator has likely updated the SSH server to listen on a non-standard port (2222), but the firewall rules were not updated to allow connections on this new port. The firewall-cmd command with the --add-port option allows traffic on a specific port through the firewall. The command should be executed on myhost to permit incoming SSH connections on port 2222.

The ~/.ssh/authorized_keys file contains SSH public keys that grant access to the user account. Removing this file ensures that no external entities can log in using previously authorized keys. The ~/.ssh/known_hosts file stores fingerprints of previously connected hosts. Removing this file ensures that SSH doesn't trust any previously connected hosts.

A is correct: When Storage=volatile is set in /etc/systemd/journald.conf, logs are kept in RAM and lost on reboot.

Incorrect Options:

B: Would cause rotation or truncation, not full loss after reboot.

C: Would stop logging entirely, not just reset after boot.

D: Journals are not stored in /tmp.

The systemctl mask postfix.service command prevents the Postfix service from being started manually or automatically by symlinking its service file to /dev/null. This ensures that even if a system restart or upgrade occurs, the service will remain disabled and will not start.

The /boot/efi directory is the mount point in a UEFI system. This directory contains the EFI System Partition (ESP), which stores boot loaders and other files required by UEFI firmware. The /sys/efi directory does not exist by default in Linux systems. The /efi directory does not exist by default in Linux systems. The /etc/efi directory does not exist by default in Linux systems. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 11: Managing the Linux Boot Process, page 398.

The command iptables -A POSTROUTING -s 172.17.0.0/16 -o eth0 -j MASQUERADE configures Network Address Translation (NAT) using iptables. This ensures that traffic from the internal network (172.17.0.0/16) going out through the eth0 interface will appear to be originating from the eth0 IP address. This is commonly used for internet-sharing or NAT setups in Linux.

The curl error "No route to host" suggests that the server is unreachable on port 443 (HTTPS).

The firewall-cmd --list-all output shows the active firewall rules:

The firewall is only allowing the following services:services: cockpit dhcpv6-client http ssh

The firewall is only allowing the following services:services: cockpit dhcpv6-client http ssh

The firewall is only allowing the following services:services: cockpit dhcpv6-client http ssh

The firewall is only allowing the following services:services: cockpit dhcpv6-client http ssh

Port 443 (HTTPS) is missing from the allowed services list.

Port 3001/tcp is open, but port 443 is not listed, which means HTTPS traffic is being blocked.

The routing table (ip route output) appears correct, as the default route is properly set to 172.31.1.1 via eth0. This rules out option B.

Option A is incorrect because eth0 is active and configured (default via 172.31.1.1 dev eth0), meaning the network interface is not down.

Option D is misleading because the firewall rules are only rejecting SSH traffic from specific IP addresses, not HTTPS traffic.

Fixing the Issue:

To allow HTTPS traffic, the administrator should enable HTTPS in the firewall:

# firewall-cmd --add-service=https --permanent

# firewall-cmd --reload

This will allow HTTPS (port 443) through the firewall.

The gzip command with the -c flag outputs the compressed data to standard output, which can then be redirected to create a .gz file. This approach maintains the original file while creating a compressed version.

SSO (Single Sign-On) allows users to authenticate once and gain access to multiple systems or services without re-authenticating. This improves user experience and reduces the number of credentials users must manage.

Source: CompTIA Linux+ XK0-005 Exam Objectives, Domain 4: Security