How Data TravelsHome Networking

One Address, a Whole House

Your router hides every device behind a single public address

Your phone, laptop and TV are all online at once, yet the internet sees just one address. How does each reply find its device?

You'll find out

  • How one address serves a whole home
  • How each reply finds its device
  • Why internet addresses ran out

Why it matters

Every home network runs on this trick. It explains why addresses ran out and why strangers can't just walk in.

About 3 min6 interactive slides · 5 questionsLesson 221 · Zone 25

Play this lesson

Free to play in your browser or on iPhone

More in this zone

  1. 217Secure MessagingEnd-to-End EncryptionEven the messaging company can't read your messages
  2. 218CosmologyThe Big Bang on Your Old TVPart of analogue TV static is the oldest light in the universe
  3. 219Thermal RadiationThe Color of HeatHot things reveal their temperature through the color they glow
  4. 220Operating SystemsThe Spinning Beach BallOne busy task can freeze an entire app
  5. 222PhotographyWhite BalanceCameras guess the color of the light to make white look white
  6. 223Materials ScienceMetal With a MemorySome metals return to their shape when warmed
  7. 224AlgorithmsHow Maps Find Your RouteYour navigation app explores outward like a ripple
  8. 225MathematicsFinding Pi With NeedlesPi appears in a game with no circles at all