UDP tests need clear goals
UDP flood testing can measure different limits. Small packets drive packets per second and stress per-packet processing. Large packets drive bandwidth and stress transit capacity. Randomized payloads test whether filters rely too heavily on signatures.
Decide which question matters before the test. A high-Gbps result does not prove high-PPS resilience, and a high-PPS result does not prove the link has enough bandwidth headroom.
Stay inside scope
UDP traffic can affect shared paths quickly, so authorization and provider coordination are essential. Test only your own addresses or provider-approved targets. Define port, rate, duration, payload shape, source ranges, and stop conditions.
If the target is a game server or custom UDP service, test the actual service path rather than a random closed port. The result should tell you how the production path behaves.
What to monitor
Watch packet rate, bandwidth, drops, NIC errors, firewall counters, CPU softirq, connection or flow-table pressure, provider mitigation events, and service-level latency. Correlate those metrics by timestamp to locate the bottleneck.
If packet drops begin at the provider while origin CPU stays idle, upstream mitigation or transit capacity is the likely limit. If CPU spikes on the host first, local filtering or kernel handling may need work.
Turn results into fixes
UDP resilience may improve through port filtering, game-aware validation, eBPF or XDP drops, provider scrubbing, anycast distribution, and tighter rate limits. Retest with the same profile after each change.