IT Crash Course Day 2: Networking Fundamentals & Operating Systems

Table of Contents

• Networking Fundamentals
  • TCP/IP
  • DNS
  • DHCP
  • IP Addressing
  • Knowledge Check: Networking Fundamentals
• OSI Model and Network Protocols
  • The 7 Layers of OSI
  • Common Network Protocols
  • Knowledge Check: OSI Model and Protocols
• Windows Operating System Basics
  • Essential Command-Line Interface
  • File Systems
  • User and Group Management
  • Event Viewer
  • Knowledge Check: Windows OS Basics
• Linux Operating System Basics
  • Linux Distributions
  • Basic Command-Line Navigation
  • File Permissions
  • Knowledge Check: Linux OS Basics
• Network Security Basics
  • Firewalls
  • Antivirus/Anti-malware
  • Password Hygiene and Security Practices
  • Knowledge Check: Network Security
• Summary and Interview Preparation Tips

Networking Fundamentals

TCP/IP

TCP/IP (Transmission Control Protocol/Internet Protocol) is the fundamental suite of protocols that powers the internet and most local networks.

Key Components:

• IP (Internet Protocol): Handles addressing and routing of packets
• TCP (Transmission Control Protocol): Ensures reliable, ordered delivery of data
• UDP (User Datagram Protocol): Provides faster, connectionless communication without guaranteed delivery

TCP/IP Model Layers:

1. Network Interface Layer: Physical and data link functionality (Ethernet, Wi-Fi)
2. Internet Layer: Addressing and routing (IP)
3. Transport Layer: End-to-end communication (TCP/UDP)
4. Application Layer: Network applications and services (HTTP, FTP, DNS)

Key Characteristics of TCP:

• Connection-oriented protocol
• Three-way handshake (SYN, SYN-ACK, ACK)
• Guarantees delivery and correct order
• Flow control and congestion management
• Used for: Web browsing, email, file transfers

Key Characteristics of UDP:

• Connectionless protocol
• No guarantee of delivery or order
• Lower overhead and latency
• Used for: Streaming media, VoIP, DNS queries

DNS

DNS (Domain Name System) translates human-readable domain names (like google.com) into machine-readable IP addresses (like 142.250.190.78).

How DNS Works:

1. User enters a URL in browser (www.example.com)
2. Computer checks local DNS cache
3. If not found, queries the configured DNS server
4. DNS server either responds with the answer or forwards the request
5. Once resolved, the IP address is returned and cached
6. Browser connects to the IP address

DNS Record Types:

• A Record: Maps hostname to IPv4 address
• AAAA Record: Maps hostname to IPv6 address
• CNAME: Canonical name (alias) record
• MX: Mail exchange record
• NS: Nameserver record
• TXT: Text record (often used for verification)

DNS Hierarchy:

• Root DNS Servers (.)
• Top-Level Domain Servers (.com, .org, etc.)
• Authoritative DNS Servers (specific domains)
• Recursive DNS Resolvers (ISP or public DNS)

DHCP

DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and network configuration to devices on a network.

DHCP Process (DORA):

1. Discovery: Client broadcasts a request for an IP address
2. Offer: DHCP server offers an IP address
3. Request: Client requests the offered IP address
4. Acknowledgment: Server confirms the address assignment

DHCP Configuration Information:

• IP address
• Subnet mask
• Default gateway
• DNS servers
• Lease duration
• Other options (NTP servers, WINS servers, etc.)

DHCP Options:

• Static Assignment: Manual IP configuration
• Dynamic Assignment: Temporary automatic assignment
• Reservation: Consistent IP address based on MAC address

IP Addressing

IPv4 Addressing:

• 32-bit address (4 octets)
• Format: xxx.xxx.xxx.xxx (each xxx is 0-255)
• Approximately 4.3 billion possible addresses
• Classes: A, B, C, D (multicast), E (experimental)
• Private ranges:
  • 10.0.0.0 to 10.255.255.255 (Class A)
  • 172.16.0.0 to 172.31.255.255 (Class B)
  • 192.168.0.0 to 192.168.255.255 (Class C)

IPv6 Addressing:

• 128-bit address (8 groups of 4 hexadecimal digits)
• Format: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx
• Approximately 340 undecillion (3.4×10^38) addresses
• Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
• Can be shortened by removing leading zeros and replacing consecutive zero groups with ::
• Example shortened: 2001:db8:85a3::8a2e:370:7334

Subnetting Basics:

• Divides a large network into smaller networks
• Uses subnet mask to define network and host portions
• Common subnet masks:
  • 255.0.0.0 (/8) - Class A
  • 255.255.0.0 (/16) - Class B
  • 255.255.255.0 (/24) - Class C

CIDR Notation:

• Classless Inter-Domain Routing
• Represented as IP address/prefix (e.g., 192.168.1.0/24)
• Prefix indicates number of bits in the network portion
• More flexible than traditional class-based addressing

Knowledge Check: Networking Fundamentals

1. Which protocol ensures reliable, ordered delivery of data packets? a) UDP b) ICMP c) TCP d) ARP

2. What does DNS primarily translate? a) IP addresses to MAC addresses b) Domain names to IP addresses c) Ports to services d) Protocols to applications

3. During which step of the DHCP process does a server offer an available IP address? a) Discovery b) Offer c) Request d) Acknowledgment

4. Which of the following is a private IPv4 address range? a) 8.8.8.0/24 b) 127.0.0.0/8 c) 192.168.0.0/16 d) 203.0.113.0/24

5. In CIDR notation, what does the "/24" in 192.168.1.0/24 represent? a) The number of available IP addresses b) The number of subnet bits c) The number of network bits d) The number of host bits

OSI Model and Network Protocols

The 7 Layers of OSI

The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes network communication functions into seven distinct layers.

Layer 7: Application Layer

• Function: Interface between network and applications
• Examples: HTTP, SMTP, FTP, DNS
• Key Concepts: Application protocols, user interfaces
• Devices: Endpoints, application firewalls

Layer 6: Presentation Layer

• Function: Data translation, encryption, compression
• Examples: SSL/TLS, JPEG, MPEG
• Key Concepts: Data format conversion, encryption/decryption
• Processes: Encoding, compression, encryption

Layer 5: Session Layer

• Function: Establishes, maintains, and terminates connections
• Examples: NetBIOS, RPC, SOCKS
• Key Concepts: Session establishment, session maintenance
• Processes: Dialog control, synchronization

Layer 4: Transport Layer

• Function: End-to-end communication, segmentation
• Examples: TCP, UDP
• Key Concepts: Connection management, error control, flow control
• Devices: Load balancers

Layer 3: Network Layer

• Function: Routing, logical addressing
• Examples: IP, ICMP, OSPF
• Key Concepts: Packet forwarding, addressing, routing
• Devices: Routers, Layer 3 switches

Layer 2: Data Link Layer

• Function: Physical addressing, error detection
• Examples: Ethernet, PPP, ARP
• Key Concepts: Frames, MAC addresses, error checking
• Devices: Switches, bridges

Layer 1: Physical Layer

• Function: Transmission of raw bits over physical medium
• Examples: Ethernet cables, fiber optics, wireless signals
• Key Concepts: Bit transmission, physical topology
• Devices: Hubs, repeaters, cables

Common Network Protocols

HTTP (Hypertext Transfer Protocol)

• OSI Layer: Application (Layer 7)
• Purpose: Web page retrieval and display
• Port: 80
• Characteristics: Stateless, text-based
• Key Components: Request methods (GET, POST, PUT, DELETE)

HTTPS (HTTP Secure)

• OSI Layer: Application (Layer 7) with Presentation (Layer 6) security
• Purpose: Secure web communications
• Port: 443
• Security: TLS/SSL encryption
• Benefits: Data integrity, authentication, encryption

FTP (File Transfer Protocol)

• OSI Layer: Application (Layer 7)
• Purpose: File transfers between client and server
• Ports: 20 (data), 21 (control)
• Characteristics: Separate control and data connections
• Security: Basic authentication, FTPS adds encryption

SFTP (SSH File Transfer Protocol)

• OSI Layer: Application (Layer 7)
• Purpose: Secure file transfers
• Port: 22
• Security: SSH encryption
• Advantage: More secure than standard FTP

SMB (Server Message Block)

• OSI Layer: Application (Layer 7)
• Purpose: File and printer sharing on Windows networks
• Ports: 445 (modern versions)
• Features: File sharing, printer sharing, named pipes
• Versions: SMBv1, SMBv2, SMBv3 (progressively more secure)

RDP (Remote Desktop Protocol)

• OSI Layer: Application (Layer 7)
• Purpose: Remote desktop access to Windows systems
• Port: 3389
• Features: Graphics transmission, encryption, authentication
• Security: Network Level Authentication (NLA)

SSH (Secure Shell)

• OSI Layer: Application (Layer 7)
• Purpose: Secure remote administration
• Port: 22
• Features: Encrypted terminal access, secure file transfers
• Common Uses: Server management, tunneling

SMTP (Simple Mail Transfer Protocol)

• OSI Layer: Application (Layer 7)
• Purpose: Email sending
• Port: 25 (unencrypted), 587 (with STARTTLS)
• Characteristics: Text-based commands
• Security: Often enhanced with TLS

IMAP/POP3 (Email Retrieval)

• OSI Layer: Application (Layer 7)
• Purpose: Email retrieval
• Ports: 143/993 (IMAP), 110/995 (POP3)
• Differences: IMAP maintains email on server, POP3 typically downloads

ICMP (Internet Control Message Protocol)

• OSI Layer: Network (Layer 3)
• Purpose: Network diagnostics and error reporting
• Examples: Ping, Traceroute
• Characteristics: No ports, uses type and code numbers

Knowledge Check: OSI Model and Protocols

1. Which layer of the OSI model handles logical addressing and routing? a) Layer 2 (Data Link) b) Layer 3 (Network) c) Layer 4 (Transport) d) Layer 5 (Session)

2. Which protocol would be most appropriate for securely transferring files between servers? a) FTP b) HTTP c) SFTP d) SMTP

3. What is the primary difference between HTTP and HTTPS? a) HTTPS uses port 443 while HTTP uses port 80 b) HTTPS encrypts data in transit while HTTP does not c) HTTPS is faster than HTTP d) HTTP supports more request methods than HTTPS

4. Which protocol is commonly used for Windows file sharing? a) FTP b) SSH c) SMB d) IMAP

5. At which OSI layer does TCP operate? a) Layer 3 (Network) b) Layer 4 (Transport) c) Layer 5 (Session) d) Layer 6 (Presentation)

Windows Operating System Basics

Essential Command-Line Interface

CMD (Command Prompt) vs PowerShell:

• CMD: Traditional command interpreter in Windows
• PowerShell: More powerful scripting environment with object-oriented approach

Essential Networking Commands:

ipconfig

• Purpose: Display IP configuration information
• Common Options:
  • ipconfig /all: Detailed configuration
  • ipconfig /release: Release DHCP lease
  • ipconfig /renew: Request new DHCP lease
  • ipconfig /flushdns: Clear DNS cache

C:\> ipconfig /all

Windows IP Configuration

   Host Name . . . . . . . . . . . : DESKTOP-PC
   Primary DNS Suffix  . . . . . . : 
   Node Type . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . : No
   WINS Proxy Enabled. . . . . . . : No

Ethernet adapter Ethernet:
   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
   Physical Address. . . . . . . . . : 00-11-22-33-44-55
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 192.168.1.100
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.1.1
   DHCP Server . . . . . . . . . . . : 192.168.1.1
   DNS Servers . . . . . . . . . . . : 192.168.1.1

ping

• Purpose: Test network connectivity
• Usage: ping hostname or ping IP_address
• Options:
  • -t: Continuous ping
  • -n count: Specify number of echo requests
  • -l size: Specify buffer size

C:\> ping google.com

Pinging google.com [142.250.190.78] with 32 bytes of data:
Reply from 142.250.190.78: bytes=32 time=15ms TTL=57
Reply from 142.250.190.78: bytes=32 time=14ms TTL=57
Reply from 142.250.190.78: bytes=32 time=14ms TTL=57
Reply from 142.250.190.78: bytes=32 time=15ms TTL=57

Ping statistics for 142.250.190.78:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 14ms, Maximum = 15ms, Average = 14ms

tracert

• Purpose: Trace route to destination
• Usage: tracert hostname or tracert IP_address
• Function: Shows path and latency to destination

C:\> tracert google.com

Tracing route to google.com [142.250.190.78]
over a maximum of 30 hops:

  1     1 ms     1 ms     1 ms  192.168.1.1
  2     8 ms     7 ms     7 ms  10.0.0.1
  3    10 ms     9 ms     9 ms  172.16.1.1
  4    15 ms    14 ms    14 ms  core1.provider.net
  5    15 ms    14 ms    15 ms  142.250.190.78

Trace complete.

netstat

• Purpose: Display network connections
• Common Options:
  • -a: Display all connections and listening ports
  • -n: Display addresses in numerical form
  • -b: Display executable involved in connection (requires admin)
  • -o: Display process ID

C:\> netstat -an

Active Connections

  Proto  Local Address          Foreign Address        State
  TCP    0.0.0.0:135            0.0.0.0:0              LISTENING
  TCP    0.0.0.0:445            0.0.0.0:0              LISTENING
  TCP    0.0.0.0:3389           0.0.0.0:0              LISTENING
  TCP    127.0.0.1:6463         0.0.0.0:0              LISTENING
  TCP    192.168.1.100:54268    142.250.190.78:443     ESTABLISHED

nslookup

• Purpose: Query DNS records
• Usage: nslookup domain_name
• Function: Resolves host names to IP addresses

C:\> nslookup microsoft.com

Server:  dns.google
Address:  8.8.8.8

Non-authoritative answer:
Name:    microsoft.com
Addresses:  2620:1ec:c11::200
          20.112.52.29

Other Essential Commands:

• systeminfo: Display system configuration information
• tasklist: Display running processes
• taskkill: Terminate processes
• sfc /scannow: System File Checker to repair Windows files
• chkdsk: Check disk for errors

File Systems

NTFS (New Technology File System)

• Primary Windows file system
• Key Features:
  • File and folder permissions
  • Encryption (EFS)
  • Compression
  • Disk quotas
  • File system journaling
  • Support for large volumes (up to 256 TB theoretically)
• Use Cases: System drives, data drives requiring security

FAT32 (File Allocation Table)

• Older file system
• Limitations:
  • 4GB maximum file size
  • 32GB maximum partition size (effectively)
  • No built-in security features
• Advantages:
  • Wide compatibility (cameras, older devices)
• Use Cases: USB drives, cross-platform compatibility

exFAT (Extended File Allocation Table)

• Modern FAT-based file system
• Features:
  • Large file size support (up to 16 exabytes)
  • No practical volume size limit
  • Better than FAT32 for flash drives
  • No security features like NTFS
• Use Cases: External drives, cross-platform storage

Comparison Table:

Feature	NTFS	FAT32	exFAT
Max File Size	16TB	4GB	16EB
Max Volume Size	256TB	32GB	128PB
Security	Yes	No	No
Journaling	Yes	No	No
Compatibility	Windows (limited on macOS/Linux)	Universal	Good cross-platform
Recommended Use	Windows system drives	Small flash drives, legacy devices	Large external drives

User and Group Management

User Account Types:

• Local Administrator: Full control over the local computer
• Standard User: Limited privileges, can run most applications
• Guest: Highly restricted (typically disabled by default)

User Management Tools:

• Computer Management Console: compmgmt.msc
• User Accounts in Control Panel
• Local Users and Groups MMC snap-in: lusrmgr.msc
• Command-line: net user commands

Common User Management Tasks:

• Create user: net user username password /add
• Delete user: net user username /delete
• Change password: net user username newpassword
• Add to group: net localgroup groupname username /add

Important Windows Groups:

• Administrators: Full control over the computer
• Users: Standard user permissions
• Remote Desktop Users: Can connect via RDP
• Backup Operators: Can back up files and directories
• Power Users: More privileges than standard users (legacy)

Security Identifiers (SIDs):

• Unique identifiers for user accounts and groups
• Format: S-1-5-21-xxxxxxxxxx-xxxxxxxxxx-xxxxxxxxxx-xxxx
• Used for access control instead of names
• Can be viewed with whoami /user command

Event Viewer

Purpose: Central location for Windows system, security, and application logs

Accessing Event Viewer:

• Type eventvwr.msc in Run dialog or search
• Administrative Tools > Event Viewer
• PowerShell: Get-EventLog cmdlet

Main Log Categories:

• Application: Events recorded by applications
• Security: Security audit events (logons, privilege use)
• System: OS component events
• Setup: OS upgrade and installation events
• Forwarded Events: Events from other computers

Event Severity Levels:

• Information: Normal operation events
• Warning: Potential issues that might need attention
• Error: Significant problems that didn't prevent operation
• Critical: Severe errors causing system/application failures
• Audit Success/Failure: Security events

Using Event Viewer for Troubleshooting:

1. Filter events by time period around issue occurrence
2. Look for Error or Critical events
3. Note Event IDs and sources
4. Research specific Event IDs online
5. Check for patterns or related events

Common Event IDs to Know:

• 4624: Successful logon
• 4625: Failed logon attempt
• 7036: Service started or stopped
• 41: System rebooted without clean shutdown
• 1074: System shutdown initiated

Knowledge Check: Windows OS Basics

1. Which command would you use to view detailed network configuration information? a) netstat -a b) ipconfig /all c) ping localhost d) tracert 127.0.0.1

2. What is the primary advantage of NTFS over FAT32? a) Better compatibility with older devices b) Faster read/write speeds c) File and folder level permissions d) Smaller cluster sizes

3. Which tool would you use to investigate application crashes on a Windows system? a) Task Manager b) Event Viewer c) Resource Monitor d) System Configuration

4. What does the following command do? net localgroup Administrators username /add a) Creates a new user called "username" b) Adds an existing user to the Administrators group c) Creates a new group called "Administrators" d) Removes a user from the Administrators group

5. In Windows Event Viewer, which log would contain information about failed login attempts? a) Application log b) System log c) Security log d) Setup log

Linux Operating System Basics

Linux Distributions

Linux Distribution (Distro): Complete Linux operating system package including the kernel, utilities, applications, and package management system.

Major Distribution Families:

Debian-based:

• Ubuntu: User-friendly, popular for desktops and servers
• Debian: Stable, focuses on free software
• Mint: Beginner-friendly desktop environment
• Package Management: APT (apt-get, apt)

Red Hat-based:

• Red Hat Enterprise Linux (RHEL): Commercial, enterprise-focused
• CentOS/Rocky Linux: Free enterprise-grade distros
• Fedora: Cutting-edge features, Red Hat testing ground
• Package Management: YUM/DNF

SUSE-based:

• SUSE Linux Enterprise: Commercial enterprise distro
• openSUSE: Community version for developers and enthusiasts
• Package Management: Zypper

Arch-based:

• Arch Linux: Rolling release, minimalist approach
• Manjaro: User-friendly Arch derivative
• Package Management: Pacman

Other Notable Distributions:

• Gentoo: Source-based distribution for advanced users
• Slackware: One of the oldest distributions, minimal
• Kali Linux: Security and penetration testing

Basic Command-Line Navigation

Terminal Access:

• GUI: Terminal application
• Text mode: Ctrl+Alt+F1 to F6
• Remote: SSH client

Basic Navigation Commands:

pwd (Print Working Directory)

• Purpose: Shows current directory
• Example: pwd → /home/username/documents

ls (List)

• Purpose: List directory contents
• Common Options:
  • ls -l: Long format with details
  • ls -a: Show hidden files
  • ls -h: Human-readable file sizes
• Example: ls -la → Show all files with details

$ ls -la
total 48
drwxr-xr-x  3 user group  4096 May 10 12:34 .
drwxr-xr-x 24 user group  4096 May 10 12:30 ..
-rw-r--r--  1 user group   220 May 10 12:32 .bash_logout
-rw-r--r--  1 user group  3771 May 10 12:32 .bashrc
drwxr-xr-x  2 user group  4096 May 10 12:34 documents
-rwxr-xr-x  1 user group 15340 May 10 12:33 script.sh

cd (Change Directory)

• Purpose: Navigate between directories
• Common Usages:
  • cd directory: Move to specified directory
  • cd ..: Move up one directory
  • cd ~: Move to home directory
  • cd /: Move to root directory
  • cd -: Move to previous directory

mkdir (Make Directory)

• Purpose: Create new directories
• Example: mkdir new_folder
• Options: mkdir -p parent/child/grandchild (create parent directories if needed)

rm (Remove)

• Purpose: Delete files and directories
• CAUTION: Deletions are permanent, no recycle bin
• Options:
  • rm file.txt: Delete a file
  • rm -r directory: Delete directory and contents recursively
  • rm -f file.txt: Force deletion without prompting

cp (Copy)

• Purpose: Copy files and directories
• Examples:
  • cp file.txt destination/
  • cp -r directory/ destination/ (copy directory recursively)

mv (Move)

• Purpose: Move/rename files and directories
• Examples:
  • mv file.txt destination/
  • mv file.txt newname.txt (rename)

cat (Concatenate)

• Purpose: Display file contents
• Example: cat filename.txt

Finding Help:

• man command: Display manual page
• command --help: Brief help information
• info command: Detailed documentation

File Permissions

Linux Permission Model: Three types of users:

• Owner: The user who owns the file
• Group: Users belonging to the file's group
• Others: All other users

Three types of permissions:

• Read (r): View file contents or list directory contents
• Write (w): Modify file or create/delete files in directory
• Execute (x): Run file as program or access directory

Permission Display:

-rwxr-xr--
 │└┬┘└┬┘└┬┘
 │ │  │  └── Others permissions (r--)
 │ │  └───── Group permissions (r-x)
 │ └──────── Owner permissions (rwx)
 └────────── File type (- for regular file, d for directory)

Common Permission Patterns:

• 755 (rwxr-xr-x): Common for executables and directories
• 644 (rw-r--r--): Common for regular files
• 600 (rw-------): Private files
• 777 (rwxrwxrwx): Full access to everyone (security risk)

Changing Permissions:

• chmod (Change Mode):
  • Symbolic: chmod u+x file (add execute to user)
  • Numeric: chmod 755 file (rwxr-xr-x)

Numeric Permission Calculation:

• Read (r) = 4
• Write (w) = 2
• Execute (x) = 1
• Add values for each permission set:
  • rwx = 4+2+1 = 7
  • r-x = 4+0+1 = 5
  • r-- = 4+0+0 = 4

Changing Ownership:

• chown (Change Owner):
  • chown user:group file
  • chown -R user:group directory (recursive)

Special Permissions:

• Set User ID (SUID): Run file with owner permissions
• Set Group ID (SGID): Run file with group permissions
• Sticky Bit: Only owner can delete files in directory

Knowledge Check: Linux OS Basics

1. Which of the following is NOT a Debian-based Linux distribution? a) Ubuntu b) Mint c) Fedora d) Debian

2. What command would you use to create a new directory called "backup" inside your home directory? a) cd ~/backup b) mkdir ~/backup c) touch ~/backup d) ls ~/backup

3. In the Linux permission model, what does the permission string "rwxr-x---" represent? a) Owner can read/write/execute, group can read/execute, others have no permissions b) Owner can read/write, group can execute, others can read c) Owner can read/execute, group can read/write, others can execute d) All users can read/write/execute

4. What is the numeric value for the permission string "rw-r-----"? a) 740 b) 640 c) 460 d) 604

5. Which command would you use to view the contents of a file named "log.txt"? a) view log.txt b) open log.txt c) cat log.txt d) read log.txt

Network Security Basics

Firewalls

Firewall Definition: Security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules.

Types of Firewalls:

• Packet Filtering: Examines packets and allows/denies based on rules
• Stateful Inspection: Tracks active connections and makes decisions
• Application Layer: Examines application-specific data
• Next-Generation Firewalls: Combines traditional firewall with additional features

Windows Firewall:

• Built-in Windows security feature
• Controls inbound and outbound connections
• Maintains separate profiles for different network types

Windows Firewall Components:

• Profiles: Domain, Private, Public
• Inbound Rules: Control incoming connections
• Outbound Rules: Control outgoing connections
• Connection Security Rules: IPsec rules

Managing Windows Firewall:

• Basic Interface: Control Panel > Windows Defender Firewall
• Advanced Interface: Windows Defender Firewall with Advanced Security
• Command Line: netsh advfirewall commands
• PowerShell: Get-NetFirewallRule, New-NetFirewallRule

Common Firewall Rules:

• Allow/block specific applications
• Allow/block specific ports
• Allow/block specific IP addresses or ranges
• Configure rules by protocol (TCP/UDP)

Best Practices:

• Use default-deny approach
• Only open necessary ports
• Regularly review firewall rules
• Test firewall configuration
• Document all rule changes

Antivirus/Anti-malware

Malware Types:

• Virus: Self-replicates by attaching to programs
• Worm: Self-replicates independently
• Trojan: Disguised as legitimate software
• Ransomware: Encrypts data for ransom
• Spyware: Collects information without consent
• Adware: Displays unwanted advertisements
• Rootkit: Provides privileged access to a system

Anti-malware Protection Layers:

• Real-time Scanning: Monitors system activity constantly
• On-demand Scanning: Manual or scheduled scans
• Behavior Monitoring: Detects suspicious behaviors
• Heuristic Analysis: Identifies unknown threats
• Cloud-based Detection: Uses online databases

Windows Security (Windows Defender):

• Built-in security solution for Windows
• Real-time protection
• Periodic scanning
• Cloud-delivered protection
• Tamper protection
• Controlled folder access

Third-party Security Solutions:

• Offer additional features beyond basic protection
• Examples: Norton, McAfee, Bitdefender, Kaspersky
• May include additional tools like VPN, password manager

Best Practices:

• Keep antivirus always enabled and updated
• Perform regular full system scans
• Update operating system and applications
• Use multiple security layers
• Be cautious with email attachments and downloads

Password Hygiene and Security Practices

Password Best Practices:

• Use long passwords (12+ characters)
• Combine uppercase, lowercase, numbers, and symbols
• Avoid using personal information
• Use different passwords for different accounts
• Change passwords periodically
• Consider using passphrases

Password Manager Benefits:

• Generates strong, unique passwords
• Securely stores passwords
• Auto-fills credentials
• Available across devices
• Examples: LastPass, Bitwarden, 1Password

Multi-Factor Authentication (MFA):

• Something you know (password)
• Something you have (phone, token)
• Something you are (biometric)
• Significantly increases security

General Security Practices:

• Keep software updated
• Use encryption when available
• Be cautious with public Wi-Fi
• Enable automatic updates
• Regularly backup important data
• Use secure browsing habits

Social Engineering Awareness:

• Be suspicious of unsolicited emails or calls
• Verify identities before providing information
• Don't click on unknown links
• Be careful with social media information
• When in doubt, verify through official channels

Physical Security:

• Lock devices when not in use
• Use screen protectors for privacy
• Secure devices in public places
• Consider cable locks for laptops
• Implement clean desk policy

Knowledge Check: Network Security

1. What is the primary function of a firewall? a) Scan files for viruses b) Control network traffic based on security rules c) Encrypt data transmitted over the network d) Detect intrusion attempts

2. Which Windows Firewall profile would typically be active when connecting to a public Wi-Fi hotspot? a) Domain profile b) Private profile c) Public profile d) Guest profile

3. Which type of malware encrypts user files and demands payment for the decryption key? a) Spyware b) Rootkit c) Worm d) Ransomware

4. What is a major advantage of using a password manager? a) It makes all your accounts use the same password b) It allows you to use simpler passwords c) It generates and stores unique passwords for different accounts d) It eliminates the need for passwords completely

5. Which of the following is an example of multi-factor authentication? a) Using a complex password with special characters b) Entering a password and a code from your phone c) Changing your password every 30 days d) Using different passwords for different accounts

Summary and Interview Preparation Tips

Key Concepts Review

Networking Fundamentals:

• TCP/IP is the foundation of internet communication
• DNS translates domain names to IP addresses
• DHCP automates network configuration
• IP addressing includes IPv4 and IPv6 with subnetting

OSI Model:

• 7 layers from Physical to Application
• Each layer has specific functions and protocols
• Common protocols operate at specific layers

Windows OS:

• Command-line tools for networking diagnostics
• File systems with different features and use cases
• User and group management for security
• Event Viewer for troubleshooting

Linux OS:

• Various distributions for different purposes
• Basic command-line navigation
• File permissions control access to resources

Network Security:

• Firewalls control network traffic
• Antivirus/anti-malware protects against threats
• Good password practices are essential

Interview Preparation Tips

Technical Knowledge:

• Review and understand all concepts in this guide
• Practice explaining complex concepts simply
• Be prepared to discuss real-world applications

Hands-On Practice:

• Use command-line tools regularly
• Set up a virtual lab for experimentation
• Troubleshoot common scenarios

Scenario Preparation:

• "How would you troubleshoot a network connectivity issue?"
• "Explain the process of setting up a secure user account."
• "What steps would you take to protect a computer from malware?"

Communication Skills:

• Practice explaining technical concepts to non-technical people
• Use analogies to simplify complex ideas
• Show logical thought processes when solving problems

Questions to Ask the Interviewer:

• "What tools does your team use for network monitoring?"
• "How does the team handle security incidents?"
• "What kind of troubleshooting scenarios are most common?"

Remember that IT support roles require both technical knowledge and soft skills like communication, problem-solving, and customer service. Be prepared to demonstrate both during interviews.

Good luck with your IT career journey!