MEPX
Chapter 2 of 10All chapters
  1. 1Layers
  2. 2Addresses
  3. 3DNS
  4. 4TCP and UDP
  5. 5Routing
  6. 6HTTP
  7. 7Wifi and local networks
  8. 8Latency and bandwidth
  9. 9Diagnosing problems
  10. 10How the internet fits together

Chapter 2 of 10

Addresses

IP, MAC and who assigns them.

Two kinds

An IP address locates a device on a network and can change. A MAC address is burned into the hardware and matters only on the local segment.

  • IPv4 looks like 192.168.1.10 and ran out years ago; IPv6 is far longer and plentiful.
  • DHCP is the service that hands out addresses automatically when a device joins.

Private and public

Home and office networks use private ranges that are not routable on the internet. NAT on the router rewrites them into one public address, which is why every device inside appears to share it.