Networking Fundamentals: TCP/IP and HTTP

Understanding networking is crucial for modern developers. Learn the basics of how the internet works.

The OSI Model

7 layers of networking:

1. Physical: Cables, signals
2. Data Link: MAC addresses
3. Network: IP addresses, routing
4. Transport: TCP/UDP
5. Session: Connection management
6. Presentation: Data formatting
7. Application: HTTP, FTP, SMTP

TCP/IP Protocol

TCP (Transmission Control Protocol)

• Reliable delivery
• Ordered packets
• Error checking

IP (Internet Protocol)

• Addressing
• Routing

HTTP Methods

GET    - Retrieve data
POST   - Create data
PUT    - Update data
DELETE - Remove data

HTTP Status Codes

• 200: OK
• 201: Created
• 400: Bad Request
• 401: Unauthorized
• 404: Not Found
• 500: Server Error

DNS (Domain Name System)

Translates domain names to IP addresses:

google.com → 142.250.190.46

Practical Commands

bash
ping google.com          # Test connectivity
traceroute google.com    # Trace route
nslookup google.com      # DNS lookup
curl https://api.example.com  # HTTP request

Security

• HTTPS encrypts data
• Firewalls filter traffic
• VPNs protect privacy