#networking

The S in HTTPS is TLS, and it buys three things people lump into "encryption": confidentiality, integrity, and authentication. The one nobody mentions, authentication, is the one that actually matters.

You pay for a gigabit connection and video calls still glitch, pages still hang, and games still lag. The number on your bill measures bandwidth, but the thing you feel is latency, and more Mbps does almost nothing to fix it.

A CDN puts copies of your content on servers near your users so the bytes travel a short distance instead of crossing an ocean every request. The thing most people miss: the bottleneck usually isn't bandwidth, it's latency, and latency is bounded by the speed of light.

DNS is the internet's phonebook, but that analogy hides the interesting part: a global lookup system, distributed across millions of servers, that resolves a name in tens of milliseconds and quietly holds the whole web together.

TCP guarantees your data arrives, in order, or dies trying. UDP just fires packets and hopes. Here is why streaming, games, DNS, and even the modern web quietly run on the one everyone calls 'unreliable'.

Most home internet plans give you 10x more download than upload, and most users never wonder why. The answer is partly engineering and partly an industry decision that’s harder to undo than to maintain.

An Ethernet cable is eight copper wires, twisted in four pairs, doing something genuinely clever. Here’s what’s inside one, why the twist matters, and which category to actually buy.