Linux+ XK0-005 Reddit Questions

The command that will set the SUID of a file named dev_team.txt with 744 access rights is chmod 4744 dev_team.txt. This command will use the chmod utility to change the file mode bits of dev_team.txt. The first digit (4) represents the SUID bit, which means that when someone executes dev_team.txt, it will run with the permissions of the file owner. The next three digits (744) represent the read, write, and execute permissions for the owner (7), group (4), and others (4). This means that the owner can read, write, and execute dev_team.txt, while the group and others can only read it.

The other options are not correct commands for setting the SUID of a file with 744 access rights. The chmod 744 --setuid dev_team.txt command is invalid because there is no --setuid option in chmod. The chmod -c 744 dev_team.txt command will change the file mode bits to 744, but it will not set the SUID bit. The -c option only means that chmod will report when a change is made. The chmod -v 4744 --suid dev_team.txt command is also invalid because there is no --suid option in chmod. The -v option only means that chmod will output a diagnostic for every file processed. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 8: Managing Users and Groups; chmod(1) - Linux manual page

The best task to perform to resolve this issue is B. Remove the entry for portal.comptia.org from the local hosts file. This is because the local hosts file has a wrong entry that maps portal.comptia.org to 10.10.10.55, which is different from the actual IP address of 192.168.1.55 that is returned by the DNS server. This causes a mismatch and prevents the workstation from accessing the website. By removing or correcting the entry in the hosts file, the workstation will use the DNS server to resolve the domain name and access the website successfully.

To remove or edit the entry in the hosts file, you need to have root privileges and use a text editor such as vi or nano. For example, you can run the command:

sudo vi /etc/hosts

and delete or modify the line that says:

10.10.10.55 portal.comptia.org

Then save and exit the file.

To enable LUKS on a USB storage device with an ext4 filesystem format, the administrator needs to perform the following steps:

• Unmount the device if it is mounted using umount /dev/sdc (D)
• Create a partition table on the device using fdisk /dev/sdc (E)
• Format the partition with LUKS encryption using cryptsetup luksFormat /dev/sdc1 (H)
• Open the encrypted partition using cryptsetup luksOpen /dev/sdc1 LUKS0001
• Create an ext4 filesystem on the encrypted partition using mkfs.ext4 /dev/mapper/LUKS0001 ©
• Mount the encrypted partition using mount /dev/mapper/LUKS0001 /mnt References:
• [CompTIA Linux+ Study Guide], Chapter 9: Securing Linux, Section: Encrypting Disks
• [How to Encrypt USB Drive on Ubuntu 18.04]

The REJECT target sends back an error packet to the source IP address, indicating that the connection is refused by the firewall. This is different from the DROP target, which silently discards the packet without any response. The RETURN target returns to the previous chain, which may or may not accept the connection. The QUEUE target passes the packet to a userspace application for further processing, which is not the desired outcome in this case.

References

• CompTIA Linux+ (XK0-005) Certification Study Guide, page 316
• iptables - ssh - access from specific ip only - Server Fault, answer by Eugene Ionichev