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Sandbox

Network lab

Ten tools, all live: from quick calculators to the isometric network builder. Build, break, observe — right in the browser.

Calculator

Subnet Calculator

Convert an IPv4/CIDR pair into network, broadcast, host range, wildcard mask, and binary form.

Beginnersubnet-calc
Protocol

DNS Lookup

Walk through recursive DNS resolution, cache hits, TTL, and common record types.

Beginnerdns-lookup
Reference

Cheat Sheet

Quick tables for OSI layers, ports, protocols, private ranges, and command examples.

Beginnercheat-sheet
Reference

Network Glossary

Plain-language definitions for core networking terms, with tiny examples.

Beginnerglossary
Command

Terminal

A safe command simulator for ping, traceroute, nslookup, ipconfig, and route inspection.

Intermediateterminal
Command

Ping & Traceroute

Run ping and traceroute against sample destinations and watch latency, loss, and route shape unfold.

Intermediateping-trace
Protocol

DHCP Simulator

Step through Discover, Offer, Request, and Acknowledge with lease details.

Intermediatedhcp-simulator
Animation

Packet Journey

Follow one HTTP request across the isometric board: headers wrap, hop, and unwrap layer by layer.

Intermediatepacket-journey
Builder

Network Builder

Drop devices onto an isometric board, cable them up, and fire packets to watch them hop — or drop.

Advancednetwork-builder
Challenge

Network Challenge

Five missions on the isometric board: build topologies under port and cable constraints, earn stars.

Advancednetwork-challenge
Packet.School

An open, interactive curriculum for computer networking.

v3.0 · MIT22 lessons live

Learn

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Simulations

  • Packet Journey
  • DNS Lookup
  • DHCP Simulator
  • Subnet Calc
  • Network Builder
  • Terminal

Project

  • About
  • Changelog
  • GitHub
  • Contributing
  • Style guide

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