One source of truth
In the authoritative server model the server holds the single canonical copy of the game world. Clients send inputs, not results, and the server decides what actually happened.
A client never tells the server it dealt damage. It says it pressed fire, and the server runs the rules to decide if the shot landed.
Why clients cannot be trusted
- A player can modify their own client to send false data.
- Network conditions differ, so two clients may disagree about timing.
- Only the server sees every player at once, so only it can resolve conflicts fairly.
What the server does each step
- Receive inputs from every client.
- Apply game rules and physics to update the canonical state.
- Send each client an authoritative snapshot of the result.
The cost is latency, since the client must wait for the server before it knows the outcome. Later lessons cover prediction and reconciliation that hide this delay.
Key idea
The server owns the true state and only accepts inputs, so a hacked client cannot rewrite reality.