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Tracks/AWS & Cloud Infrastructure
Intermediate 1 minTroubleshooting

An EC2 instance can't reach the internet. How do you debug VPC connectivity?

Scenario

You have SSH access via bastion. The EC2 is in a private subnet with a NAT Gateway supposedly configured.

The interviewer asks

“A newly launched EC2 instance in your VPC cannot make outbound internet requests. The instance is running, SSH works from your bastion, but curl fails. Walk me through your debugging process.”

The 30-second answer

Check Security Groups, NACL rules, Route Tables, NAT Gateway status and association, Internet Gateway attachment, and instance's public IP or NAT attachment. Work through the OSI model — IP connectivity before DNS.

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  • The voiced mock interview (1 min)
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  • Animated architecture diagrams
  • The whole conversation, 4 turns
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  • 1 copy-ready command snippet
  • 2 follow-up questions they'll ask next
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More AWS & Cloud Infrastructure interview questions

  • What are the steps to launch an EC2 instance?
All AWS & Cloud Infrastructure questions

Linux commands for this track

  • aws configure Set up AWS CLI credentials, region and profiles
  • aws s3 Copy, sync and list files in Amazon S3
  • aws ec2 Find, start and stop EC2 instances from the CLI
  • aws iam Inspect users, roles and policies, and debug access
  • aws eks Connect kubectl to EKS and manage cluster access
  • az Manage Azure resources with the Azure CLI
  • gcloud Manage Google Cloud with the gcloud CLI