Game servers are some of the most attacked infrastructure on the internet. Rival communities, angry players, and extortionists target them precisely because they are fragile: a few seconds of packet loss is enough to empty a server.
Web applications fail gracefully. A slow API returns a timeout and the user retries. A game server fails loudly. Tick rate drops, rubber-banding starts, and sixty players disconnect at once. That difference is why stress testing a game server demands a different approach than stress testing a website.
Three Properties That Change the Test
- UDP-first protocolsReal-time games trade reliability for latency. State updates flow over UDP, so your test must generate UDP traffic, not just HTTP requests.
- Stateful sessionsEvery connected player holds memory and CPU on the server. Simulating a player spike is as important as simulating a packet flood.
- Fixed tick budgetsA Minecraft server has 50 milliseconds per tick. When processing exceeds that budget, the game degrades for everyone online.
What to Measure by Game
Each engine exposes different health signals. The table below lists the default ports and the metric that best reflects player experience under load.
| Game | Protocol and port | Metric to watch |
|---|---|---|
| Minecraft Java | TCP 25565, query UDP | TPS, ticks per second, target 20 |
| FiveM | UDP 30120 | Server frame time and hitch warnings |
| Rust | UDP 28015 | Framerate and entity queue length |
| CS2 and Source engine | UDP 27015 | Tick time, target under 15.6 ms at 64 tick |
| Valheim | UDP 2456 to 2457 | Send and receive queue growth |
| ARK Survival | UDP 7777, query 27015 | Server FPS and player ping spread |
Ports listed are defaults. Always confirm the actual binding on your own server before building a test profile.
A Testing Methodology That Reflects Reality
The goal is not to crash your server. The goal is to learn the exact load level where player experience starts to degrade, then decide whether your mitigation and hosting plan can absorb it.
- Record a clean baseline with normal player count: tick rate, frame time, bandwidth, and packet loss.
- Simulate a player spike first. Bots or headless clients reveal CPU and memory limits before any flood begins.
- Add a controlled UDP flood from a second machine you own, starting at 100 Mbps and doubling every two minutes.
- Watch the player-facing metric, not the network graph. TPS or tick time tells you when players feel pain.
- Note the exact threshold where the game degrades and where your mitigation engages.
- Stop the test, restore normal service, and document the results for your hosting provider.
Protection Layers Worth Testing Against
A stress test is only useful if it validates a defense. These are the mitigation layers game communities rely on, and each one changes what your test should look like.
- OVH Game shieldIncluded with OVH dedicated servers, with per-game filters for Minecraft, Rust, FiveM, and Source engine titles. Test that the filter profile matches your actual port map.
- Path.netAnycast DDoS mitigation popular with FiveM and Minecraft networks. Verify that legitimate player latency stays acceptable while filters are active.
- Cloudflare SpectrumReverse proxy for TCP and UDP applications. Confirm your plan covers your ports and measure the added latency for players.
- TCPShield and NeoProtectMinecraft-specific proxies that hide your origin IP. The most important test is confirming the origin firewall only accepts traffic from the proxy.
Legal boundary: every test in this guide assumes you own the server or hold written authorization from the hosting provider. Directing flood traffic at a server you do not control is a crime in the US, UK, EU, and most other jurisdictions, regardless of how small the test is.