What it is
During an attack, traffic destined for the target is rerouted through a scrubbing facility with far more capacity than the origin. Filters there discard what they judge malicious and forward the rest through a clean channel. Scrubbing may be always-on or triggered on detection, and the trigger delay matters — an attack that peaks in seconds can do its damage before rerouting completes.
Why it matters for Minecraft
It is genuinely good at volume. Where it struggles is judgement: generic scrubbing filters on packet shape, source reputation and rate, none of which distinguish a join flood from a popular server at peak. To a scrubber, ten thousand valid TCP connections carrying valid game packets is a busy evening.
The difference that matters
Whether the filter understands the protocol it is protecting. A scrubber that implements the Minecraft protocol can read the handshake, evaluate the hostname, distinguish a status ping from a login and hold suspicious joins for verification. One that does not is a very large, very fast packet counter — see protocol-aware filtering for why that gap decides outcomes.
Common questions
Is always-on scrubbing better than on-demand?+
For Minecraft, usually yes. On-demand scrubbing has to detect and reroute first, and a join flood can exhaust a server well inside that window. Always-on means there is no window.
Does scrubbing add latency?+
Some, depending on how far the traffic detours. Always-on filtering that sits inline on a short path adds very little; on-demand rerouting to a distant facility can add a lot, which players notice.