A small reference notebook
A small reference on names, connections and the boundaries between them.
This notebook collects short explanations that are useful to revisit. Each note focuses on one small question, with plain navigation and local resources.
A name is a label that people can keep while an address changes. A DNS lookup connects those two ideas. Keeping them separate makes a connection problem easier to describe: first record the name you requested, then the address your resolver returned. Neither fact, by itself, tells you whether the service at that address is healthy.
A certificate check relates a connection to the name requested by the client. It is useful to preserve that check when investigating a failure. Removing the check can make one error disappear while losing the very property being examined.