CompTIA A+ Core 2

SOP

• Standard Operating Procedure (SOP)

• Step-by-step instructions for completing a task

• Ensures tasks comply with policy

• Most IT procedures should be governed by SOPs

SLA

• Service Level Agreements (SLA)

• Defines the required level of service

• Agreement between:

  • Internal departments

  • External third-party vendors

• Specifies how service performance is measured

AUP

• Acceptable Use Policy (AUP)

• Defines what users are allowed to use services/resources for

• Applies to employees or customers

• Controls use of:

  • Computers and devices

  • Internet access

  • Telephone services

  • Network resources

NTFS

• New Technology File System (NTFS)

• Microsoft file system for Windows

• Supports very large files and volumes

• Key features:

  • Journaling → improves recovery after crashes/power loss

  • Snapshots → allows previous file versions/recovery

  • Security → permissions, ownership, auditing, quotas, encryption

  • POSIX support → some UNIX/Linux compatibility

  • Indexing → faster file searches

  • Dynamic disks → combine storage from multiple physical disks

• Main drawback → limited support outside Windows

• macOS: Can read but normally cannot write to NTFS

• Linux: Can support NTFS to varying degrees

ReFS

• Resilient File System (ReFS)

• Newer Microsoft file system

• Designed for large-scale and specialized storage

• Key benefits:

  • Resiliency → detects and repairs corruption

  • High performance → optimized for large datasets/workloads

  • Scalability → supports extremely large amounts of data

• NTFS remains more common for general Windows use

FAT32

• Older File Allocation Table system

• Maximum file size → 4 GB − 1 byte

• Typically supports volumes up to 2 TB

• Does not provide NTFS-level security or reliability features

• Useful for:

  • Boot/system partitions

  • Removable drives

  • Memory cards

  • Devices using different operating systems

exFAT

• Extended File Allocation Table

• Designed for removable drives and flash media

• Supports large volumes

• Recommended maximum → 512 TB

• Supports access permissions

• Does not support encryption

XFS

• Introduced in 1993

• 64-bit journaling file system

• Designed for high performance and scalability

• Default file system for Red Hat Enterprise Linux (RHEL)

• Supported by other Linux distributions

NFS

• Network File System (NFS)

• Allows Linux to mount remote storage

• Makes a remote file resource appear like a local file system

• Useful for accessing files stored on another computer/system

APFS

• Apple File System (APFS)

• Apple's proprietary file system

• Used by Mac computers

• Supports:

  • Journaling

  • Snapshots

  • Permissions/ownership

  • Encryption

Robocopy

• Heavy-duty backups, network transfers, full mirroring

Xcopy

• Quick, basic file and folder copying

ipconfig

• IP address

• Subnet mask

• Default gateway

ipconfig /all

• DHCP information

• DNS servers

• MAC address

• NetBIOS status

RTT

• Round-Trip Time

tracert

• Command-line tool used to trace the path packets take to a destination.

• Helps identify routing problems.

• Can use:

  • IP address

  • FQDN

• tracert displays:

• Hop number

• Router/host interface

• Response time in milliseconds (ms)

Pathping

• Alternative to tracert

• First traces the route, then pings each hop multiple times.

• Measures:

  • Round-trip time (RTT)

  • Link latency

  • Packet loss at each hop

• Useful for identifying where along the route latency or packet loss occurs.

Higher-Layer Network Troubleshooting

3 Main Areas of Failure

• Security

  • Firewall may be blocking the connection.

  • Security software/hardware may be blocking traffic.

  • Incorrect proxy settings may prevent access.

• Name Resolution (DNS)

  • DNS failure means you can connect using an IP address but not a hostname.

  • Example:

    • ping 8.8.8.8 → works

    • ping google.com → fails

  • Indicates a possible DNS/name-resolution problem.

• Application / OS

  • The operating system or application providing the service may have failed.

  • If the server itself cannot be reached, the OS or network may be the problem.

  • If the server can be reached but a specific service cannot, the service process may have crashed.

nslookup

• Command-line tool used to troubleshoot DNS.

• Can be used:

  • Interactively

  • Directly from Command Prompt

netstat

• netstat investigates open ports and network connections on the local computer.

• Useful for checking:

  • File-sharing ports

  • Email ports

  • Client connections to a server

RDP

• Remote Desktop Protocol

• Windows uses RDP for Remote Desktop functionality.

• Start Remote Desktop using:

  • Remote Desktop Connection

  • mstsc.exe

• Connect using:

  • IP address

  • FQDN

VNC

• Virtual Network Computing

• VNC is an alternative to RDP for remote desktop access.

• macOS Screen Sharing uses VNC.

• VNC operates over TCP port 5900.

• Security varies between VNC implementations.

  • Not all VNC versions support secure connections.

  • macOS Screen Sharing is encrypted.

NLA

• Network Level Authentication

• You can choose whether to:

  • Allow older RDP clients, or

  • Require clients that support NLA.

• NLA authenticates the user before creating the desktop session.

• This helps protect against Denial-of-Service (DoS) attacks.

WinRM

• Windows Remote Management

• Microsoft's implementation of the WS-Management protocol.

• Allows systems to exchange and access management information remotely.

• Included in current Windows versions.

• Microsoft's implementation of the WS-Management protocol.

• Allows systems to exchange and access management information remotely.

• Included in current Windows versions.

RMM

• Remote Monitoring & Management

• Primarily designed for Managed Service Providers (MSPs).

• MSPs provide IT support for multiple client organisations.

• RMM tools can:

  • Separate/manage different client accounts.

  • Monitor systems remotely.

  • Record support activity.

  • Track/report billable support work.

WOL

• Wake on LAN

• Can remotely wake/start compatible machines.

• May also support:

  • Firmware/BIOS configuration

  • Firmware updates

  • OS deployment

SPICE

• Simple Protocol for Independent Computing Environments

• Used for remote display and interaction with virtual machines (VMs).

• Allows users/admins to monitor and interact with VMs remotely, including across the Internet.

Windows Event Viewer

• Event Viewer is used to view and troubleshoot Windows system events and errors.

• (eventvwr.msc)

System Information Tool

• Provides a detailed overview of a Windows computer's hardware and software.

• (msinfo32.exe)

Task Manager

• Purpose: Monitors CPU, memory, disk, network, and running processes.

• Performance tab: Provides detailed information about:

  • CPU

  • Memory (RAM)

  • Disk

  • Network

  • GPU

Performance Monitoring Tools

• Provides more detailed monitoring than Task Manager.

• Shows resource performance graphs and statistics.

• Can track:

  • Processes and threads

  • Memory usage

  • Hard page faults per second

• A continuous increase in certain statistics may indicate a performance problem.

• (resmon.exe)

Performance Monitor

• Provides real-time charts and long-term performance logging.

• More detailed than Task Manager's Performance tab.

• Helps identify system bottlenecks, such as:

  • Slow CPU

  • Slow disk

  • Network problems

• Useful for determining which hardware or component may need upgrading.

• (perfmon.exe)

System Configuration

• Purpose: Controls settings that affect Windows startup and booting.

• Main use: Diagnostic troubleshooting, not usually for permanent configuration changes.

• Open it: Search System Configuration or run msconfig.exe

Windows Recovery Environment

• Windows Recovery Environment (WinRE)

• Used when Windows cannot boot normally.

• Can be accessed through:

  • Recovery partition

  • Repair/recovery disk

  • Windows installation media

• You may need to change the BIOS/UEFI boot priority to boot from recovery media.

Security Controls

Security controls are safeguards that reduce or prevent security risks.

• Physical: Control access to physical locations.

  • Examples: Fences, doors, locks

• Procedural: Security measures carried out by people.

  • Examples: Incident response, management oversight, security training

• Logical: Digital/technical controls enforced by systems.

  • Examples: Authentication, antivirus, firewalls

CIA Triad

• Confidentiality: Only authorized users can access sensitive information.

• Integrity: Data remains accurate and trustworthy.

• Availability: Systems and resources are accessible when needed.

Identity & Access Management

• Identity & Access Management (IAM)

• IAM ensures users have the right access to the right resources at the right time.

  • Identification: Identifies users, devices, and applications.

  • Authentication: Verifies who someone is.

    • Passwords

    • Biometrics

    • Multi-factor authentication (MFA)

  • Authorization: Determines what the user is allowed to do.

  • Access Control: Enforces those permissions and restrictions.

Access Control Lists

• Access Control Lists (ACLs)

• A permission determines what access an account has to a resource.

• An ACL contains rules called Access Control Entries (ACEs).

• Each ACE identifies a subject and its permitted actions.

• Subjects can include:

  • Users

  • Computers

  • Services

• Windows uses a unique Security Identifier (SID) for accounts.

Symmetric Encryption

• Uses one secret key to both encrypt and decrypt data.

• The key must remain secret.

• If the key is stolen or lost, security can be compromised.

• Main weakness: secure key distribution and storage.

• Main advantage: very fast, making it ideal for large amounts of data.

• Example: AES (Advanced Encryption Standard).

Asymmetric Encryption

• Uses a key pair:

  • Public key: Can be shared openly.

  • Private key: Must remain secret.

• The keys are mathematically linked.

• Data encrypted with one key can only be reversed using the paired key.

• Main advantage: secure communication without having to secretly distribute the public key.

• The private key cannot be derived from the public key.

Cryptographic Hashing

• Converts data of any size into a fixed-length hash value.

• A cryptographic hash is one-way — the original data cannot practically be recovered from the hash.

• Useful when the original data doesn't need to be retrieved.

• Common use: secure password storage.

• Common algorithms:

  • SHA-256

  • SHA-3

Just-in-Time (JIT) Access

• Grants access only when it is needed.

• Access is available for only as long as required.

• Reduces the time an account has elevated access.

• Supports the principle of least privilege.

Privileged Access Management (PAM)

• Secures, controls, and monitors privileged accounts.

• Important because compromised administrator accounts can cause major system damage.

• Helps control and reduce unnecessary administrative access.

User Account Control (UAC)

• Windows security feature that protects against malware and unauthorized privileged actions.

• Implements least privilege by requiring explicit approval for elevated tasks.

• A Security Shield icon indicates actions protected by UAC.

Security Assertions Markup Language

• Security Assertions Markup Language (SAML)

• Enables a form of SSO between an Identity Provider (IdP) and a Service Provider (SP).

Single Sign-On

• Single Sign-On (SSO)

• Authenticate once → Access multiple services.

• Windows domain SSO commonly uses Kerberos + Active Directory.

• Advantages:

  • Fewer passwords to manage.

  • Easier user experience.

• Disadvantage:

  • If the account is compromised, multiple services may be compromised.