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NetworkingFundamentalsTCP/IP

Networking Fundamentals Every Developer Should Know

AITECHJ Team•April 28, 2025•10 min read

Understanding networking is essential for building reliable, performant web applications and debugging production issues.

The OSI Model (Simplified)

  • - **Layer 7 (Application)**: HTTP, HTTPS, WebSocket, gRPC
  • - **Layer 4 (Transport)**: TCP, UDP
  • - **Layer 3 (Network)**: IP addressing, routing
  • - **Layer 2 (Data Link)**: Ethernet, MAC addresses

TCP vs UDP

TCP provides reliable, ordered delivery with connection management. Use it for web traffic, file transfers, and APIs.

UDP provides fast, connectionless delivery without guarantees. Use it for real-time applications like video streaming, gaming, and DNS lookups.

DNS Resolution

When you type a URL in your browser: 1. Browser checks its DNS cache 2. OS resolver checks the system cache 3. Query goes to the configured DNS server 4. Recursive resolution through the DNS hierarchy 5. IP address is returned and cached

HTTPS and TLS

TLS (Transport Layer Security) provides encryption, authentication, and integrity for network communications. Understanding the TLS handshake helps debug certificate issues and optimize connection performance.

Key Concepts for Developers

  • - **Load Balancing**: Distributing traffic across multiple servers
  • - **CDNs**: Caching content closer to users
  • - **Firewalls**: Controlling network access
  • - **VPNs**: Secure tunnels between networks
  • - **NAT**: Translating between private and public IP addresses

These fundamentals will help you design better systems and troubleshoot issues more effectively.