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CompTIA Linux+ XK0-004 Exam

CompTIA Linux+ XK0-004 Exam which is related to CompTIA Linux+ Certification. This exam validates the Candidate ability to configure, monitor, and support servers running the Linux operating system. It also deals with the knowledge and skills of security, kernel modules, storage and visualization, device management at an enterprise level, git and automation, networking and firewalls, server side and command line, server (vs. client-based) coverage, troubleshooting and SELinux.

CompTIA XK0-004 Exam Syllabus Topics:

TopicDetails

Hardware and System Configuration - 21%

Explain Linux boot process concepts.1.Boot loaders
  • GRUB
  • GRUB2

2.Boot options

  • UEFI/EFI
  • PXE
  • NFS
  • Boot from ISO
  • Boot from HTTP/FTP

2.File locations

  • /etc/default/grub
  • /etc/grub2.cfg
  • /boot
  • /boot/grub
  • /boot/grub2
  • /boot/ef

3.Boot modules and files

  • Commands
    mkinitrd
    dracut
    grub2-install
    grub2-mkconfig
  • initramfs
  • efi files
  • vmlinuz
  • vmlinux

4.Kernel panic

Given a scenario, install, configure, and monitor kernel modules.1.Commands
  • lsmod
  • insmod
  • modprobe
  • modinfo
  • dmesg
  • rmmod
  • depmod

2.Locations

  • /usr/lib/modules/[kernelversion]
  • /usr/lib/modules
  • /etc/modprobe.conf
  • /etc/modprobe.d/
Given a scenario, configure and verify network connection parameters.1.Diagnostic tools
  • ping
  • netstat
  • nslookup
  • dig
  • host
  • route
  • ip
  • ethtool
  • ss
  • iwconfig
  • nmcli
  • brctl
  • nmtui

2.Configuration files

  • /etc/sysconfig/network-scripts/
  • /etc/sysconfig/network
  • /etc/hosts
  • /etc/network
  • /etc/nsswitch.conf
  • /etc/resolv.conf
  • /etc/netplan
  • /etc/sysctl.conf
  • /etc/dhcp/dhclient.conf

3.Bonding

  • Aggregation
  • Active/passive
  • Load balancing
Given a scenario, manage storage in a Linux environment.1.Basic partitions
  • Raw devices
  • GPT
  • MBR

2.File system hierarchy

  • Real file systems
  • Virtual file systems
  • Relative paths
  • Absolute paths

3.Device mapper

  • LVM
  • mdadm
  • Multipath

4.Tools

  • XFS tools
  • LVM tools
  • EXT tools
  • Commands
    mdadm
    fdisk
    parted
    mkfs
    iostat
    df
    du
    mount
    umount
    lsblk
    blkid
    dumpe2fs
    resize2fs
    fsck
    tune2fs
    e2label

5.Location

  • /etc/fstab
  • /etc/crypttab
  • /dev/
  • /dev/mapper
  • /dev/disk/by-
    id
    uuid
    path
    multipath
  • /etc/mtab
  • /sys/block
  • /proc/partitions
  • /proc/mounts

6.File system types

  • ext3
  • ext4
  • xfs
  • nfs
  • smb
  • cifs
  • ntfs
Compare and contrast cloud and virtualization concepts and technologies.1.Templates
  • VM
  • OVA
  • OVF
  • JSON
  • YAML
  • Container images

2.Bootstrapping

  • Cloud-init
  • Anaconda
  • Kickstart

3.Storage

  • Thin vs. thick provisioning
  • Persistent volumes
  • Blob
  • Block

4.Network considerations

  • Bridging
  • Overlay networks
  • NAT
  • Local
  • Dual-homed

5.Types of hypervisors
6.Tools

  • libvirt
  • virsh
  • vmm
Given a scenario, configure localization options.1.File locations
  • /etc/timezone
  • /usr/share/zoneinfo

2.Commands

  • localectl
  • timedatectl
  • date
  • hwclock

3.Environment variables

  • LC_*
  • LC_ALL
  • LANG
  • TZ

4.Character sets

  • UTF-8
  • ASCII
  • Unicode

Systems Operation and Maintenance - 26%

Given a scenario, conduct software installations, configurations, updates, and removals.1.Package types
  • .rpm
  • .deb
  • .tar
  • .tgz
  • .gz

2.Installation tools

  • RPM
  • Dpkg
  • APT
  • YUM
  • DNF
  • Zypper

3.Build tools

  • Commands
    make
    make install
    ldd
  • Compilers
  • Shared libraries

4.Repositories

  • Configuration
  • Creation
  • Syncing
  • Locations

5.Acquisition commands

  • wget
  • curl
Given a scenario, manage users and groups.1.Creation
  • useradd
  • groupadd

2.Modification

  • usermod
  • groupmod
  • passwd
  • chage

3.Deletion

  • userdel
  • groupdel

4.Queries

  • id
  • whoami
  • who
  • w
  • last

5.Quotas

  • User quota
  • Group quota

6.Profiles

  • Bash parameters
    User entries
    - .bashrc
    - .bash_profile
    - .profile
  • Global entries
    /etc/bashrc
    /etc/profile.d/
    /etc/skel
    /etc/profile

7.Important files and file contents

  • /etc/passwd
  • /etc/group
  • /etc/shadow
Given a scenario, create, modify, and redirect files.1.Text editors
  • nano
  • vi

2.File readers

  • grep
  • cat
  • tail
  • head
  • less
  • more

3.Output redirection

  • <
  • >
  • |
  • <<
  • >>
  • 2>
  • &>
  • stdin
  • stdout
  • stderr
  • /dev/null
  • /dev/tty
  • xargs
  • tee
  • Here documents

4.Text processing

  • grep
  • tr
  • echo
  • sort
  • awk
  • sed
  • cut
  • printf
  • egrep
  • wc
  • paste

5.File and directory operations

  • touch
  • mv
  • cp
  • rm
  • scp
  • ls
  • rsync
  • mkdir
  • rmdir
  • ln
    Symbolic (soft)
    Hard
  • unlink
  • inodes
  • find
  • locate
  • grep
  • which
  • whereis
  • diff
  • updatedb
Given a scenario, manage services.1.Systemd management
  • Systemctl
    Enabled
    Disabled
    Start
    Stop
    Mask
    Restart
    Status
    Daemon-reload
  • Systemd-analyze blame
  • Unit files
    Directory locations
    Environment parameters
  • Targets
  • Hostnamectl
  • Automount

2.SysVinit

  • chkconfig
    on
    off
    level
  • Runlevels
    Definitions of 0–6
    /etc/init.d
    /etc/rc.d
    /etc/rc.local
    /etc/inittab
    Commands
    -runlevel
    -telinit
  • Service
    Restart
    Status
    Stop
    Start
    Reload
Summarize and explain server roles.1.NTP
2.SSH
3.Web
4.Certificate authority
5.Name server
6.DHCP
7.File servers
8.Authentication server
9.Proxy
10.Logging
11.Containers
12.VPN
13.Monitoring
14.Database
15.Print server
16.Mail server
17.Load balancer
18.Clustering
Given a scenario, automate and schedule jobs.1.cron
2.at
3.crontab
4.fg
5.bg
6.&
7.kill
8.Ctrl+c
9.Ctrl+z
10.nohup
Explain the use and operation of Linux devices.1.Types of devices
  • Client devices
  • Bluetooth
  • WiFi
  • USB
  • Monitors
  • GPIO
  • Network adapters
  • PCI
  • HBA
  • SATA
  • SCSI
  • Printers
  • Video
  • Audio

2.Monitoring and configuration tools

  • lsdev
  • lsusb
  • lspci
  • lsblk
  • dmesg
  • lpr
  • lpq
  • abrt
  • CUPS
  • udevadm
    add
    reload-rules
    control
    trigger

3.File locations

  • /proc
  • /sys
  • /dev
  • /dev/mapper
  • /etc/X11

4.Hot pluggable devices

  • /usr/lib/udev/rules.d (System rules - Lowest priority)
  • /run/udev/rules.d (Volatile Rules)
  • /etc/udev/rules.d (Local Administration - Highest priority)
  • /etc/udev/rules.d
Compare and contrast Linux graphical user interfaces.1.Servers
  • Wayland
  • X11

2.GUI

  • Gnome
  • Unity
  • Cinnamon
  • MATE
  • KDE

3.Remote desktop

  • VNC
  • XRDP
  • NX
  • Spice

4.Console redirection

  • SSH port forwarding
    Local
    Remote
    X11 forwarding
    VNC

5.Accessibility

Security - 19%

Given a scenario, apply or acquire the appropriate user and/or group permissions and ownership.1.File and directory permissions
  • Read, write, execute
  • User, group, other
  • SUID
  • Octal notation
  • umask
  • Sticky bit
  • SGID
  • Inheritance
  • Utilities
    chmod
    chown
    chgrp
    getfacl
    setfacl
    ls
    ulimit
    chage

2.Context-based permissions

  • SELinux configurations
    disabled
    permissive
    enforcing
  • SELinux policy
    targeted
  • SELinux tools
    setenforce
    getenforce
    sestatus
    setsebool
    getsebool
    chcon
    restorecon
    ls -Z
    ps -Z
  • AppArmor
    aa-disable
    aa-complain
    aa-unconfined
    /etc/apparmor.d/
    /etc/apparmor.d/tunables

3.Privilege escalation

  • su
  • sudo
  • wheel
  • visudo
  • sudoedit

4.User types

  • Root
  • Standard
  • Service
Given a scenario, configure and implement appropriate access and authentication methods.1.PAM
  • Password policies
  • LDAP integration
  • User lockouts
  • Required, optional, or sufficient
  • /etc/pam.d/
  • pam_tally2
  • faillock

2.SSH

  • ~/.ssh/
    known_hosts
    authorized_keys
    config
    id_rsa
    id_rsa.pub
  • User-specific access
  • TCP wrappers
  • /etc/ssh/
    ssh_config
    sshd_config
  • ssh-copy-id
  • ssh-keygen
  • ssh-add

3.TTYs

  • /etc/securetty
  • /dev/tty#

4.PTYs
5.PKI

  • Self-signed
  • Private keys
  • Public keys
  • Hashing
  • Digital signatures
  • Message digest

6.VPN as a client

  • SSL/TLS
  • Transport mode
  • Tunnel mode
  • IPSec
  • DTLS
Summarize security best practices in a Linux environment.1.Boot security
  • Boot loader password
  • UEFI/BIOS password

2.Additional authentication methods

  • Multifactor authentication
    Tokens
    -Hardware
    -Software
    OTP
    Biometrics
  • RADIUS
  • TACACS+
  • LDAP
  • Kerberos
    kinit
    klist

3.Importance of disabling root login via SSH
4.Password-less login

  • Enforce use of PKI

5.Chroot jail services
6. No shared IDs
7.Importance of denying hosts
8.Separation of OS data from application data

  • Disk partition to maximize system availability

9.Change default ports
10.Importance of disabling or uninstalling unused and unsecure services

  • FTP
  • Telnet
  • Finger
  • Sendmail
  • Postfix

11.Importance of enabling SSL/TLS
12.Importance of enabling auditd
13.CVE monitoring
14.Discouraging use of USB devices
15.Disk encryption

  • LUKS

16.Restrict cron access
17.Disable Ctrl+Alt+Del
18.Add banner
19.MOTD

Given a scenario, implement logging services.1.Key file locations
  • /var/log/secure
  • /var/log/messages
  • /var/log/[application]
  • /var/log/kern.log

2.Log management

  • Third-party agents
  • logrotate
  • /etc/rsyslog.conf
  • journald
    journalctl

3.lastb

Given a scenario, implement and configure Linux firewalls.1.Access control lists
  • Source
  • Destination
  • Ports
  • Protocol
  • Logging
  • Stateful vs. stateless
  • Accept
  • Reject
  • Drop
  • Log

2.Technologies

  • firewalld
    Zones
    Run time
  • iptables
    Persistency
    Chains
  • ufw
    /etc/default/ufw
    /etc/ufw/
  • Netfilter

3.IP forwarding

  • /proc/sys/net/ipv4/ip_forward
  • /proc/sys/net/ipv6/conf/all/forwarding

4.Dynamic rule sets

  • DenyHosts
  • Fail2ban
  • IPset

5.Common application firewall configurations

  • /etc/services
  • Privileged ports
Given a scenario, backup, restore, and compress files.1.Archive and restore utilities
  • tar
  • cpio
  • dd

2.Compression

  • gzip
  • xz
  • bzip2
  • zip

3.Backup types

  • Incremental
  • Full
  • Snapshot clones
  • Differential
  • Image

4.Off-site/off-system storage

  • SFTP
  • SCP
  • rsync

5.Integrity checks

  • MD5
  • SHA

Linux Troubleshooting and Diagnostics - 20%

Given a scenario, analyze system properties and remediate accordingly.1.Network monitoring and configuration
  • Latency
    Bandwidth
    Throughput
  • Routing
  • Saturation
  • Packet drop
  • Timeouts
  • Name resolution
  • Localhost vs. Unix socket
  • Adapters
    RDMA drivers
  • Interface configurations
  • Commands
    nmap
    netstat
    iftop
    route
    iperf
    tcpdump
    ipset
    Wireshark
    - tshark
    netcat
    traceroute
    mtr
    arp
    nslookup
    dig
    host
    whois
    ping
    nmcli
    ip
    tracepath

2.Storage monitoring and configuration

  • iostat
  • ioping
  • IO scheduling
    cfq
    noop
    deadline
  • du
  • df
  • LVM tools
  • fsck
  • partprobe

3.CPU monitoring and configuration

  • /proc/cpuinfo
  • uptime
  • loadaverage
  • sar
  • sysctl

4.Memory monitoring and configuration

  • swapon
  • swapoff
  • mkswap
  • vmstat
  • Out of memory killer
  • free
  • /proc/meminfo
  • Buffer cache output

5.Lost root password

  • Single user mode
Given a scenario, analyze system processes in order to optimize performance.1.Process management
  • Process states
    Zombie
    Uninterruptible sleep
    Interruptible sleep
    Running
  • Priorities
  • Kill signals
  • Commands
    nice
    renice
    top
    time
    ps
    lsof
    pgrep
    pkill
  • PIDs
Given a scenario, analyze and troubleshoot user issues.1.Permissions
  • File
  • Directory

2.Access

  • Local
  • Remote

3.Authentication

  • Local
  • External
  • Policy violations

4.File creation

  • Quotas
  • Storage
  • Inode exhaustion
  • Immutable files

5.Insufficient privileges for authorization

  • SELinux violations

6.Environment and shell issues

Given a scenario, analyze and troubleshoot application and hardware issues.1.SELinux context violations
2.Storage
  • Degraded storage
  • Missing devices
  • Missing volumes
  • Missing mount point
  • Performance issues
  • Resource exhaustion
  • Adapters
    SCSI
    RAID
    SATA
    HBA
    - /sys/class/scsi_host/host#/scan
  • Storage integrity
    Bad blocks

3.Firewall

  • Restrictive ACLs
  • Blocked ports
  • Blocked protocols

4.Permission

  • Ownership
  • Executables
  • Inheritance
  • Service accounts
  • Group memberships

5.Dependencies

  • Patching
  • Update issues
  • Versioning
  • Libraries
  • Environment variables
  • GCC compatibility
  • Repositories

6.Troubleshooting additional hardware issues

  • Memory
  • Printers
  • Video
    GPU drivers
  • Communications ports
  • USB
  • Keyboard mapping
  • Hardware or softwarecompatibility issues
  • Commands
    dmidecode
    lshw

Automation and Scripting - 14%

Given a scenario, deploy and execute basic BASH scripts.1.Shell environments and shell variables
  • PATH
  • Global
  • Local
  • export
  • env
  • set
  • printenv
  • echo

2.#!/bin/bash
3.Sourcing scripts
4.Directory and file permissions

  • chmod

5.Extensions
6.Commenting

  • #

7.File globbing
8.Shell expansions

  • ${}
  • $()
  • ` `

8.Redirection and piping
9.Exit codes

  • stderr
  • stdin
  • stdout

10.Metacharacters
11.Positional parameters
12.Looping constructs

  • while
  • for
  • until

13.Conditional statements

  • if
  • case

14.Escaping characters

Given a scenario, carry out version control using Git.1.Arguments
  • clone
  • push
  • pull
  • commit
  • merge
  • branch
  • log
  • init
  • config

2.Files

  • gitignore
  • .git/
Summarize orchestration processes and concepts.1.Agent
2.Agentless
3.Procedures
4.Attributes
5.Infrastructure automation
6.Infrastructure as code
7.Inventory
8.Automated configuration management
9.Build automation

Reference: https://certification.comptia.org/certifications/linux#overview

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