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Cloud networking, at packet level

Master cloud networking by fixing real-world production outages.

Reading about VPC routing does not build intuition. Debugging a broken one does. Every lab hands you a Terraform file that deploys a genuinely broken environment and an incident ticket — no hints, no answer key until you ask for it.

Diagnostic labs
1
Learning tracks
4
Deep dives
3

Trace a real failure — the outage behind Lab 01:

packet-trace10.0.11.34:49820 → 52.94.236.248:443
  1. EC2Batch instance10.0.11.34 · subnet-private-a
  2. SGSecurity group egresssg-app · allow 0.0.0.0/0
  3. NACLNetwork ACLdefault · allow all
  4. RTBPrivate route table0.0.0.0/0 → nat-0f8e
  5. NATNAT Gatewaynat-0f8e · state: available
  6. RTBNAT Gateway's own subnet route0.0.0.0/0 → itself (no IGW route)
  7. DESTapi.processor.example52.94.236.248:443

Run the trace to see where the packet dies.

Lab of the weekFreeAssociate~20 min

INC-1043

Lab 01: The Misplaced NAT Gateway

A batch job in a private subnet cannot reach a third-party API. The route table looks correct, the security groups are wide open, and the NAT Gateway reports Available. Find out why every outbound connection still hangs.

AWS VPCNAT Gateway
Open the ticket

Reported symptom

Outbound API calls from the private subnet time out after deploying the new VPC

Reported by Payments Platform