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Network L6 NETWORK-009 · 24 min

An SNI routing problem where the TLS handshake fails only on certain domains

A situation where the certificate is valid but SNI routing is wrong, so only some domains fail.

NetworkPlatform ReliabilityLevel 6Pro24 min
Scenario

A scenario that narrows down the root cause, centered on validating the per-domain certificate and proxy routing configuration together, in the situation of an SNI routing problem where the TLS handshake fails only on certain domains.

What to check first
  • Identify the primary failure signal in the TLS Routing 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

Choose the smallest safe recovery action first, then record the prevention work that reduces repeat incidents.

Questions worth viewing together
Why does SNI matter in partial TLS failures?

The same IP can present different certificates and upstream routes depending on the requested hostname.