Common Network Protocols Explained | TCP, UDP, HTTP, DNS & More

Key Takeaways

Welcome back to Bazai. Today we're breaking down one of the foundations of the internet, common network protocols. Every website you open, every API call, every secure connection, every message, and every VPN tunnel depends on these protocols working together. In the next 3 minutes, I'll walk you through the most important protocols, what layer they belong to, and where they're used in real systems. Let's begin. At the transport layer, the core protocols are TCP, UDP, and QIC. TCP is connectionoriented and reliable. It uses the three-way handshake sac and guarantees order delivery. This is used for HTTP, databases, email, and anything where correctness matters. UDP is connectionless and fast. There's no handshake, no retransmission, and no ordering guarantees. This is perfect for DNS, streaming, gaming, and real-time systems. QIC is the modern transport used by HTTP/3. It runs over UDP but adds encryption, multiplexing and zero roundtrip handshakes. This reduces latency and improves performance on mobile and lossy networks. On top of transport, we have the web and security layer. HTTP is the protocol of the web request and response over TCP or QUIC. Everything from browsers to REST APIs runs on HTTP. TLS provides encryption, authentication and integrity. It secures HTTP into HTTPS and protects data from eavesdropping and tampering. Without TLS, the modern internet simply cannot exist. For secure access and file movement, we use SSH on port 22 for secure remote login and command execution. This is the backbone of DevOps and server management. SFTP runs on top of SSH and provides encrypted file transfers. SMB is used for network file sharing especially in enterprise and Windows environments. These protocols enable secure administration and shared storage across networks. Next is DNS, the phone book of the internet. DNS translates domain names into IP addresses using UDP or TCP on port 53. But traditional DNS is unencrypted. That's why we now use DNS over HTTPS. Do encrypts DNS queries over HTTPS preventing ISPs and attackers from spying on which websites you visit. Four modern applications and real-time systems. GRRPC is used for high performance serviceto-service communication in microervices. MQTT is a lightweight publish subscribe protocol used in IoT systems. Websocket enables full duplex communication over HTTP. Perfect for chats, dashboards, and live feeds. Web RDC powers realtime audio, video, and peer-to-peer communication. These protocols enable low latency real-time distributed systems.