Networking

Contents

Part one · Foundations

1. 1Names into addresses3 lessons○○○

   DNS resolution told as a concierge story, the same question as bytes on the wire, and the telegram written by hand.

   • 01DNS Resolution8 Q
   • 02DNS on the wire9 Q
   • 03Write the telegram yourself8 Q

   DNS ResolutionDNS TelegramDNS Wire FormatWrite the Telegram Yourself
2. 2How a packet finds a house7 lessons○○○○○○○

   Postcards and phone calls, the handshake in real bytes, the parcel's route across the world, and your own router's life.

   after Names into addresses▶ Watch the video

   • 01TCP vs UDP, and the 3-way handshake9 Q
   • 02The page that never arrived (TCP reliable delivery)8 Q
   • 03How a parcel finds any house on earth8 Q
   • 04Inside your building (your router's life)11 Q
   • 05The corridor inside the building (frames, switches and VLANs)7 Q
   • 06Inside one postal company (distance-vector, link-state, and ICMP)8 Q
   • 07The hold line (the listen queue, and the SYN flood)8 Q

   Postcards and Phone CallsTCP HandshakeThe Parcel's JourneyInside Your Building
3. 3Faster, private, everywhere7 lessons○○○○○○○

   Why distance costs time, how a call goes private, how the web outgrew the phone call, and one address answered from a thousand doors.

   after How a packet finds a house

   • 01Reading a book aloud to America8 Q
   • 02Where the time goes (the four delays, and the buffer that fills)8 Q
   • 03The whisper code (how a call goes private)11 Q
   • 04What a request actually says (HTTP)8 Q
   • 05How the web outgrew the phone call9 Q
   • 06One address, a thousand doors10 Q
   • 07The key at the door (SSH: keys, known hosts, the agent and tunnels)7 Q

   The Long-Distance ReadingThe Whisper CodeOutgrowing the Phone CallOne Address A Thousand Doors
4. 4The whole trip2 lessons○○

   Every lesson so far, in one page load: a real fetch timed phase by phase back to the lesson behind each, then the same walk as a ladder for the page that will not load.

   after Faster, private, everywhere

   • 01One click, every layer (what happens when you load a page)8 Q
   • 02It won't load: the ladder (network debugging)8 Q

Part two · Build

1. 5Build it yourself5 lessons○○○○○

   Five small programs that rebuild what the track explained: a reliable page over lossy postcards, a resolver that walks from the root, ping and traceroute, and a reader for a packet capture.

   after The whole trip

   • 01Build it: the page that gets through (stop-and-wait, then a window)7 Q
   • 02Build it: only the lost page (selective repeat, loss and reordering)7 Q
   • 03Build it: the concierge who walks (a recursive resolver)7 Q
   • 04Build it: ping, and the parcel that dies on purpose (ICMP and traceroute)7 Q
   • 05Build it: read the capture (a pcap reader, layer by layer)7 Q