At a glance
- Did you know
- Checking credentials at the edge stops credential stuffing before it reaches the app.
- Rule of thumb
- Limit login attempts per account and per IP, and offer MFA.
- Watch out
- Credential stuffing without lockout; token checks add latency.
Its settings in ScaleMySystems
What you can change on it in the lab, and what each number does.
- Concurrency (slots)
- Calls it can work on at once (per instance when autoscaling). Needed slots ≈ calls per second × seconds each takes. Extra calls wait in the queue, then are rejected.
- Queue capacity
- Calls allowed to wait for a free slot. A bigger queue absorbs bursts but adds waiting time; 0 rejects straight away.
- vCPU
- CPU cores available. Needed ≈ calls per second × CPU per request ÷ 1000. Above about 90% busy it slows down and may crash.
- Latency (p50) (ms)
- Typical time one call takes here, before any calls it makes itself. Slots are held for this long.
- Latency (p99) (ms)
- The slowest 1% of calls. Callers must set their timeout above this or they cut off healthy calls.
- Attack block rate
- Share of the attacks it covers that it stops. The rest pass through and are served like real users.
- False positives (real users blocked)
- Share of real users it wrongly blocks. Stricter rules raise the block rate and this together.
Full lesson coming soon
Lessons are being added one component at a time: how it works, its settings, a live exercise to break and fix it, interview questions and a short check. See the Circuit breaker lesson for what one looks like.