Understanding what a computer network is, why networks exist, and how data is shared across devices. Basics of communication between computers

LAN (Local Area Network): Small geographic area like an office.

WAN (Wide Area Network): Covers large geographic areas like the internet.

MAN (Metropolitan Area Network): Network spanning a city.

PAN (Personal Area Network): Very close range like Bluetooth devices

Explains different ways devices can be connected in a network, affecting performance and fault tolerance.

OSI Model: Conceptual framework of 7 layers (Physical to Application) describing network communication.

TCP/IP Model: More practical 4-layer model used on the internet

Explanation of IPv4 addressing (e.g., 192.168.1.1) and subnet masks (e.g., 255.255.255.0).

Understanding how subnetting divides networks for efficient routing

DHCP: Automatically assigns IP addresses to devices.

DNS: Translates human-readable domain names (like google.com) into IP addresses.

HTTP (Port 80): Web browsing protocol.

HTTPS (Port 443): Secure web browsing using SSL/TLS.

FTP (Ports 20 & 21): File transfer protocol.

SMTP (Port 25): Email sending protocol.

SNMP (Port 161): Network management protocol.

Basics of Wi-Fi, wireless standards (802.11a/b/g/n/ac), and security protocols like WPA2

Fundamentals of securing networks, including firewalls, VPNs, encryption, and intrusion detection

Explains Virtual Private Networks (VPNs) for secure remote connections and how remote access works.

Common tools like ping, traceroute, ipconfig, and their use in diagnosing network problems.

Basic Nmap Commands for Network Scanning (Kali Linux):

nmap -sP 192.168.1.0/24 — Ping scan to find live hosts in the subnet

nmap -sS 192.168.1.10 — TCP SYN scan (stealth scan) on target IP

nmap -sV 192.168.1.10 — Service version detection

nmap -O 192.168.1.10 — OS detection

nmap -p 1-1000 192.168.1.10 — Scan ports 1 to 1000 on target IP

nmap –script vuln 192.168.1.10 — Run vulnerability scripts against target