XK0-005 Exam Dumps - CompTIA Linux+ Exam

These commands can display all the firewall rules applied to the Linux servers, depending on which firewall service is being used.

The firewall-cmd command is a utility for managing firewalld, which is a dynamic firewall service that supports zones and services. The --list-all option will show all the settings and rules for the default zone, or for a specific zone if specified. For example, firewall-cmd --list-all --zone=public will show the rules for the public zone1.

The ufw command is a frontend for iptables, which is a low-level tool for manipulating netfilter, the Linux kernel’s packet filtering framework. The status option will show the status of ufw and the active rules, or the numbered rules if verbose is specified. For example, ufw status verbose will show the numbered rules and other information2.

The other options are incorrect because:

A. ufw limit

This command will limit the connection attempts to a service or port using iptables’ recent module. It does not display any firewall rules2.

B. iptables -F

This command will flush (delete) all the rules in the selected chain, or all chains if none is given. It does not display any firewall rules3.

C. systemctl status firewalld

This command will show the status of the firewalld service, including whether it is active or not, but it does not show the firewall rules4.

F. iptables -A

This command will append one or more rules to the end of the selected chain. It does not display any firewall rules3.

Creating a snapshot of the current state of the code in Git is best achieved with the git tag command, which is often used to mark release points or stable versions in a project. Tags are helpful for referencing points in history without affecting the branch structure. Unlike branches, which are for active development, tags are commonly used to mark versions for future reference or deployment. Reference: CompTIA Linux+ Study Guide.

The slowness is caused by the CPU being overloaded. The iostat command shows that the CPU utilization is 100%, which means that there are more processes competing for CPU time than the CPU can handle. The other options are incorrect because:

The system is not running out of swap space, as shown by the iostat command, which shows that there is no swap activity (si and so columns are zero).

The memory is not exhausted, as shown by the free -m command, which shows that there is still available memory (avail column) and free buffer/cache memory (buff/cache column).

The processes are not paging, as shown by the vmstat command, which shows that there are no major page faults (majflt column) and no swap activity (si and so columns). References: CompTIA Linux+ Study Guide, Fourth Edition, page 417-419, 424-425.

The administrator should use the command mount disk by device-id to resolve the device mismatch issue and mount the disk. The issue is caused by the cloned server having a different device name for the disk than the original server. The output of blkid shows that the disk has the device name /dev/sdb1 on the cloned server, but the output of cat /etc/fstab shows that the disk is expected to have the device name /dev/sda1. The command mount disk by device-id will mount the disk by using its unique identifier (UUID) instead of its device name. The UUID can be obtained from the output of blkid or lsblk -f. The command will mount the disk to the specified mount point (/data) and resolve the issue. The other options are incorrect because they either do not mount the disk (fsck -A), do not use the correct identifier (mount disk by-label or mount disk by-blkid), or do not exist (mount disk by-blkid). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 10: Managing Storage, pages 318-319.

For repairing XFS filesystems, the appropriate command is xfs_repair. Since the /opt/finapp directory resides on an XFS filesystem (indicated in the mount output), xfs_repair is suitable for diagnosing and fixing corruption in XFS inodes and extent trees. Using fdisk or fsck.ext4 is not appropriate for XFS filesystems, as these commands are intended for partitioning and ext4 filesystems, respectively. Reference: CompTIA Linux+ Study Guide.

The command that will back up the directory /data and all its contents to /backup/data on a remote server named remote is rsync -a /data remote:/backup/. This command uses the rsync tool, which is a remote and local file synchronization tool. It uses an algorithm to minimize the amount of data copied by only moving the portions of files that have changed. The -a option stands for archive mode, which preserves the permissions, ownership, timestamps, and symbolic links of the files. The /data argument specifies the source directory to be backed up, and the remote:/backup/ argument specifies the destination directory on the remote server. The rsync tool will create a subdirectory named data under /backup/ on the remote server, and copy all the files and subdirectories from /data on the local server.

The other options are not correct commands for backing up a directory to a remote server. The scp -p /data remote:/backup/data command will copy the /data directory as a file named data under /backup/ on the remote server, not as a subdirectory with its contents. The -p option preserves the permissions and timestamps of the file, but not the ownership or symbolic links. The ssh -i /remote:/backup/ /data command will try to use /remote:/backup/ as an identity file for SSH authentication, which is not valid. The cp -r /data /remote/backup/ command will try to copy the /data directory to a local directory named /remote/backup/, not to a remote server. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 18: Automating Tasks; rsync(1) - Linux manual page

To obtain information about the UUIDs of all disks attached to a Linux system, the administrator can run the command blkid (B). This will display the block device attributes, including the UUID, label, type, and partition information. The other commands are not related to this task. References:

[CompTIA Linux+ Study Guide], Chapter 5: Managing Filesystems and Logical Volumes, Section: Identifying Disks by UUID

[How to Use blkid Command in Linux]

The firewall-cmd command is used to manage firewalld, which is a firewall service for Linux systems that provides dynamic and persistent configuration of firewall rules. Firewalld uses zones and services to define different levels of trust and access for network connections.

To permit access temporarily to an application running on port 1234/TCP on a Linux server, the systems administrator can use the firewall-cmd --add-port=1234/tcp command. This command will add a rule to the default zone (usually public) that allows incoming traffic on port 1234/TCP. The rule will only be effective until the next reload or restart of firewalld. To make the rule permanent, the administrator can add the --permanent option to the command. The statement C is correct.

The statements A, B, and D are incorrect because they do not permit access to port 1234/TCP. The firewall-cmd --new-service=1234/tcp command does not exist. The firewall-cmd --service=1234 --protocol=tcp command does not work because 1234 is not a predefined service name in firewalld. The firewall-cmd --add-whitelist-uid=1234 command does not exist. References: [How to Use FirewallD to Manage Firewall in Linux]