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Network L4 NETWORK-1512 · 10 min

A Cloudflare Tunnel stays healthy and WebSockets still fail because an internal rewrite strips the Upgrade header

The connector is up, but one rewrite path removes the header pair required for WebSocket upgrades.

NetworkFoundation OpsLevel 4Free10 min
Scenario

Only one routed hostname behind Cloudflare Tunnel breaks WebSockets after rewrite rules were added.

What to check first
  • Identify the primary failure signal in the The Tunnel Stayed Open and the Upgrade Request Lost Its Secret Handshake in the Hallway scenario.
  • Separate visible symptoms from the underlying technical dependency.
  • Describe the safest recovery path and the follow-up prevention work.
Checking checklist
  1. Summarize the current impact and the last known change.
  2. Collect direct evidence from logs, runtime state, and configuration before changing anything.
  3. Separate immediate recovery from permanent prevention work.
Recovery and prevention

Inspect rewrite and header preservation before blaming the connector.

Questions worth viewing together
Should I translate commands, logs, or product names?

No. Keep commands, logs, file names, APIs, and product names unchanged, then explain the reasoning in the selected UI language.

What should the answer focus on?

State the root cause, the evidence that supports it, and the safest recovery direction.

Why can the scenario remain in the original language?

The source scenario is treated as an incident artifact. Guidance, checklist, hints, and explanations can be localized around it.