Internet Protocols

The routing protocol that makes the internet work, exchanging routing and reachability information between autonomous systems.

Network management protocol used to automatically assign IP addresses and other configuration to devices joining a network.

Hierarchical distributed naming system that translates human-readable domain names into IP addresses for locating internet resources.

DNS over HTTPS (DoH) is an IETF protocol (RFC 8484) that encrypts DNS queries by sending them as HTTPS requests rather than plaintext UDP packets. Standard DNS (port 53) is unencrypted – any network observer can see every domain a user resolves. DoH wraps DNS queries in HTTPS, making them indistinguishable from regular web traffic. DoH is enabled by default in Firefox and Chrome and is deployed by Cloudflare (1.1.1.1), Google (8.8.8.8), and NextDNS.

High-performance, open-source RPC framework from Google using HTTP/2 for transport and Protocol Buffers for serialization. Supports unary, server streaming, client streaming, and bidirectional streaming RPCs.

Application-layer protocol for transmitting hypermedia documents, such as HTML. Foundation of the World Wide Web.

Binary-framed version of HTTP that multiplexes multiple requests over a single TCP connection, compresses headers with HPACK, and eliminates head-of-line blocking at the application layer. Supersedes HTTP/1.1 for all modern web traffic.

HTTP/3 is the third major version of HTTP, defined by RFC 9114 (June 2022). It runs over QUIC (RFC 9000) instead of TCP. QUIC is a UDP-based transport that provides multiplexing without head-of-line blocking, 0-RTT connection establishment, and built-in TLS 1.3 encryption. HTTP/3 is now the default on Cloudflare, Fastly, and most major CDNs. Approximately one-third of all web traffic uses HTTP/3 as of 2026.

Supporting protocol in the Internet Protocol suite used by network devices to report errors and operational information about IP packet processing.

The principal communications protocol in the Internet Protocol suite for relaying datagrams across network boundaries.

Protocol for synchronizing clocks of computer systems over packet-switched, variable-latency data networks.

General-purpose transport protocol built on UDP providing multiplexed streams, built-in TLS 1.3 encryption, and 0-RTT connection resumption.

Simple Mail Transfer Protocol is the standard protocol for sending and relaying email across the internet. SMTP handles the transfer of messages from mail clients to servers (submission) and from server to server (relay). Defined by RFC 5321, SMTP uses a command-response model with 3-digit reply codes to signal success, failure, or error.

Protocol for collecting and organizing information about managed devices on IP networks and modifying that information to change device behavior.

Cryptographic network protocol for secure remote login, command execution, and file transfer over unsecured networks.

Deprecated cryptographic protocol developed by Netscape in 1995. All versions (SSL 2.0, SSL 3.0) have critical vulnerabilities and are prohibited by RFC 7568. The modern replacement is TLS (Transport Layer Security).

Connection-oriented transport protocol providing reliable, ordered, error-checked delivery of data between applications over IP networks.

Cryptographic protocol providing secure communication over computer networks, ensuring privacy, data integrity, and authentication between applications.

Connectionless transport protocol that provides best-effort delivery of independent datagrams across IP networks.

WebSocket is a full-duplex communication protocol over a single persistent TCP connection. After an HTTP/1.1 upgrade handshake, either endpoint can send frames at any time without polling. WebSocket is the standard protocol for real-time web applications: chat, live dashboards, multiplayer games, financial tickers, and collaborative editing.