Networking

A computer network is a group of devices connected together to share data and resources. Examples include home WiFi, office networks and the internet.

• LAN (Local Area Network): Small area like home, school or office
• WAN (Wide Area Network): Large area across cities or countries
• Internet: The global network connecting all networks
• Intranet: Private internal company network

Every device connected to a network has an IP address (like a house address). It allows devices to find and communicate with each other.

• Public IP – visible on the internet
• Private IP – used inside home/office network
• Static IP – fixed address
• Dynamic IP – changes automatically

• HTTP: Loads websites
• HTTPS: Secure encrypted website communication
• DNS: Converts domain names into IP addresses
• TCP: Reliable data transfer
• UDP: Faster but less reliable transfer

Ports act like doors on a computer allowing services to communicate.

• 80 – HTTP
• 443 – HTTPS
• 22 – SSH (remote login)
• 21 – FTP (file transfer)

• Router: Connects networks to the internet
• Switch: Connects devices inside a network
• Firewall: Filters traffic for security
• Load Balancer: Distributes traffic across servers

• VPN – secure remote connection
• NAT – hides internal IP addresses
• Packet filtering – blocks malicious traffic