HTTP: messages and meaning
Requests, responses, status codes, caching, and the difference between an application protocol and its transport.
Networking essentials
Small notes on how the web works.
A concise reference for reading HTTP messages and understanding DNS. Start with a concept, then follow the bytes.
DNS: names and records
Resolvers, authoritative servers, common record types, and why a DNS answer can change over time.
A useful layered model
DNS helps find an address. An IP network carries packets to that address. TCP or QUIC provides a transport; TLS authenticates a peer and protects data in transit. HTTP defines the meaning of requests and responses above those layers.
These layers solve different problems. A successful DNS lookup does not imply that a service is reachable, and a successful connection does not imply that an application request will succeed.