A Minecraft server is a program that holds the world and decides what is true in it. Your game is a client: it draws what the server tells it and asks permission for everything else. Almost every confusing thing about hosting follows from that split.
Who does what
| The server | Your client |
|---|---|
| Stores the world and every block in it | Draws what it is sent |
| Decides whether your attack hit | Predicts what will happen so it feels instant |
| Runs mobs, crops, redstone | Renders them |
| Holds inventories and player data | Displays them |
| Enforces permissions and rules | Asks, and accepts the answer |
Why that split matters to you
When you place a block, your client draws it immediately and tells the server. If the server disagrees — you did not have the block, the area is protected, you were somewhere else — the block disappears again a moment later. That flicker is the two views disagreeing, and it is the visible edge of the whole architecture.
It also explains the two kinds of «lag». If the server is slow, everyone experiences it together and things happen late. If your own machine is slow, only you see stuttering and everyone else is fine.
Consequences worth knowing
- The server runs whether or not you are online. That is what you are paying for.
- Anything you can do in game, the server had to allow. Cheats that «work» are usually server-side gaps.
- Plugins run inside the server, not on players' machines. Nobody has to install anything.
- Mods usually run in both places, which is why players need the same mods you do.
- The world only exists on the server. Your client keeps no copy worth recovering.
The server holds all the state. Restarting rebuilds that state from what is on disk, which clears anything that got into a strange condition in memory. It is not a superstition — it genuinely resets the only place the world exists.