Trace a failed request through packet size, flow state, idle connections, proxy identity, TLS name, address family, and transport choice. Choose the observation that proves the user path, not only one healthy component.
Review these lessons
- Path MTU: find the packet size that breaks an otherwise healthy route
- Connection tracking: separate host flow exhaustion from application limits
- Proxy idle timers: stop reused sockets from failing the next request
- Forwarded client IP: trust a hop, not a request header
- TLS name selection: test SNI, certificate, and HTTP host together
- Dual-stack rollout: prove IPv4 and IPv6 reach the same service contract
- HTTP/3 rollout: keep a tested TCP route when UDP fails
- PROXY protocol: accept client metadata only from the intended load balancer
Other checks
Common Mistakes
- Do not infer end-to-end health from a small probe.
- Do not accept untrusted proxy metadata as client identity.