Names, addresses, and connections
Why a domain name is a lookup, why HTTPS matters, and why the first visit is always slower.
Machines on the internet find each other by number, not by name. A domain name is a human convenience layered on top, and turning one into the other is a real network round trip that costs real milliseconds.
- DNS lookup
Name to address. Cached afterwards. - TCP handshake
Agreeing to talk at all. - TLS handshake
Agreeing to talk privately: the S in HTTPS. - First byte
Only now does the server start answering.
Every one of those steps is a trip across physical distance. Light is fast but not instant: a round trip from London to Virginia is roughly 80 milliseconds no matter how good your code is. Four round trips before a single byte of content is why "where is the server?" is a performance question, not a trivia question.
HTTPS is not optional and not just about passwords. Without it, anything between you and the server (an ISP, an airport wifi router, a government) can read and modify the page. Modern browsers now assume it, and some features simply refuse to run without it.
What to remember
- A domain name is a lookup, and lookups are cached in places you do not control.
- The first connection pays for DNS, TCP, and TLS before any content moves.
- Physical distance sets a floor on speed that no amount of code removes.
Terms in this lesson
Show field notes toggles a search param the loader reads. With it off, the slow promise is never created, so nothing streams.