Webhooks: Events Fire, Nothing Runs
Every delivery is a 2xx on one side and nothing on the other. Follow the signature, live, right below.
Symptom
The platform is sending webhook events and the receiver logs are clean, but the automation never triggers.
Your mission
Inspect, recover, then verify
Format
Linux shell
Investigate before you configure.
Use the CLI evidence to isolate the fault, make the smallest safe correction, then verify the network state changed.
Observe the symptom and link state.
Diagnose by comparing the protocol evidence.
Verify the expected device state and confirm the original symptom is resolved.
Console access: Linux
This workspace stacks for portrait phones. Rotate to landscape for the full split-screen console.
Need a hint?
Reveal the root cause when you're ready.
Try the investigation first, then use this as your escape hatch, not a dead end.
Lab debrief
Turn the session into a repeatable troubleshooting pattern.
Use this reference after your attempt: first explain the symptom, then verify the evidence, then confirm the repair.
The problem
A webhook receiver is registered to trigger automation when a platform event fires. The platform shows the events being sent, but the automation never runs, and there are no errors in the receiver's logs.
What you'll practice
- Register a webhook and inspect its delivery attempts
- Validate incoming webhook signatures and secrets correctly
- Return correct status codes so retry logic behaves
- Trace an event from platform through receiver to handler
- Diagnose deliveries that are silently rejected
The topology
A Cisco platform emits events to a containerized webhook receiver that triggers automation, with a delivery log on the platform side, so you trace an event end to end instead of guessing where it stopped.
Commands to run yourself
The real diagnostic commands for this lab, copy-paste ready. Run these in the same order to reproduce the investigation on your own session.
curl -s https://platform.lab.example/api/webhooks/deliveries | jq .journalctl -u webhook-receiver -n 5 --no-pagernode sign.mjs --secret $RECEIVER_SECRETTopology diagram
Fact-checked references
The commands and behaviour in this lab were checked against these primary references.
Frequently asked
Why are the receiver logs clean?
Because the request is rejected at the edge, before it reaches the handler that logs. Signature or secret validation that fails silently looks exactly like nothing arriving.
Does this map to DEVCOR?
Yes. Webhooks, signature validation and event-driven design are core DevNet Professional (350-901) application topics.
Ready to run this lab yourself?
No setup, no image sourcing. Book a session or ask for a live demo.