Field
Networks & the Internet
How the internet actually works — the chain of inventions, each one solving the limit the last hit, that carries a request from your browser to a server and back.
20 articles · 40 widgets
VPNs and Tunneling
A VPN builds an encrypted tunnel across the public internet by wrapping one network's packets inside another's — encapsulation — so a remote device can reach a private network as if plugged into the office wall.
HTTP/2 and HTTP/3: Reinventing the Web's Transport
The verbs and headers of HTTP are the same as 1997, but the transport under them was re-engineered twice. HTTP/2 multiplexes many streams over one TCP connection; HTTP/3 throws out TCP entirely for QUIC over UDP to escape head-of-line blocking.
BGP: How the Internet's Networks Agree on Routes
The internet is a mesh of ~75,000 independently run networks. BGP is how they advertise reachable prefixes to each other and negotiate routes — driven by business policy, not shortest path, and held together by trust.
Wi-Fi: Networking Through the Air
How Wi-Fi carries a link-layer over a shared radio medium, why it must avoid collisions instead of detecting them, and why the rated speed on the box is a ceiling everyone shares, not a promise to each device.
Peer-to-Peer: The Internet Without a Center
In a peer-to-peer network there is no central server — every node is both client and server. BitTorrent splits a file into pieces and a swarm trades them, so the more people want a file, the faster everyone gets it.
Ethernet: How Machines Share a Wire
The layer beneath IP: how a packet physically crosses a local network, why every device has a 48-bit MAC address, how a switch learns where each machine lives, and how ARP turns an IP into the MAC needed to actually deliver a frame.
Firewalls: Filtering the Traffic
A firewall decides which traffic may pass by matching packets against rules on address, port, and protocol. The real leap is memory: a stateful firewall welcomes the replies to connections you started while turning away strangers who arrive uninvited.
CDNs: Bringing the Web Closer
A load balancer scales a site in one place, but distance sets a floor on latency that no amount of hardware can beat. CDNs scale geographically — caching content at hundreds of edge locations near users, and steering each request to the closest one.
Ping and Traceroute: Seeing the Network
Ping times an echo to tell you a host is alive and how far away it feels; traceroute lists every router in between by deliberately expiring packets one hop farther each time. Both ride on ICMP.
Load Balancers and Reverse Proxies
One server has a ceiling and a single point of failure. Reverse proxies and load balancers turn many fragile machines into one fast, reliable service by spreading load and health-checking around failures.
Email: The Internet's Oldest Application
Email is a distinct application on the internet's plumbing, older than the web. It relays store-and-forward from mail server to mail server via a DNS MX lookup, and by original design never checked who the sender claimed to be — which is why SPF, DKIM, and DMARC exist.
Certificates and the Chain of Trust
TLS hands your browser a public key and says 'encrypt to me' — but anyone can generate a key. Certificates and a chain of signatures reaching back to a short list of preinstalled authorities are what tie that key to a real identity.
DHCP: How Your Device Joins a Network
How a device with no address at all joins a network: the DORA handshake that leases it an IP address, subnet mask, default gateway, and DNS server automatically — on a lease that quietly expires.
TLS: Encrypting the Web
Plaintext HTTP let anyone on the path read your passwords. TLS wraps the connection in encryption by using slow asymmetric crypto only to authenticate the server and agree a key, then switching to fast symmetric crypto for the data.
NAT: How Billions Share Four Billion Addresses
There are about four billion possible IPv4 addresses and far more than four billion connected devices — yet everything works. Network Address Translation is the stopgap hiding in every home router that lets a whole network share a single public address, disambiguated by port.
HTTP and the World Wide Web
The web is one application running on top of the internet's plumbing. HTTP is how a browser asks a server for a resource — a stateless request and response that cookies and the Host header quietly extend into logins and shared hosting.
DNS: The Internet's Phone Book
Humans use names; the network routes to numbers. DNS bridges the gap with a distributed, delegated tree — no single machine holds the whole thing, and caching makes it feel instant.
TCP: Reliability on an Unreliable Network
IP loses, duplicates and reorders packets and promises to fix none of it. TCP turns that mess into a perfect ordered byte stream — entirely at the two endpoints, without ever changing the network in between.
IP Addresses and Routing
IP gives every device an address and lets routers forward packets hop by hop toward it — best-effort, connectionless, and with no single router that knows the whole route.
Packet Switching
Why the internet chops your data into hundreds of independently-routed packets instead of reserving a wire for you, and how that one choice buys both efficiency and resilience.