AWS Certified Advanced Networking - Specialty ANS-C01Demo

By Amazon · Question Mode

QuestionQ232

Network Management and Operation

A company hosts an application on Amazon EC2 instances. A network engineer deploys a NAT gateway in the application’s VPC to replace self-managed NAT instances. After the engineer redirects traffic from the self-managed NAT instances to the NAT gateway, users start reporting problems.

While troubleshooting, the network engineer finds that the connection to the application closes after about 6 minutes of inactivity.

What should the network engineer do to fix this issue?

  • A Check for increases in the IdleTimeoutCount Amazon CloudWatch metric for the NAT gateway. Configure TCP keepalive on the application EC2 instances.
  • B Check for increases in the ErrorPortAllocation Amazon CloudWatch metric for the NAT gateway. Configure an HTTP timeout value on the application EC2 instances.
  • C Check for increases in the PacketsDropCount Amazon CloudWatch metric for the NAT gateway. Configure an HTTPS timeout value on the application EC2 instances.
  • D Check for decreases in the ActiveConnectionCount Amazon CloudWatch metric for the NAT gateway. Configure UDP keepalive on the application EC2 instances.
Explanation

Amazon VPC NAT gateways time out connections that have been idle for 350 seconds (about 6 minutes). An increasing IdleTimeoutCount indicates these idle expirations, and TCP keepalive configured for less than 350 seconds maintains the connection before the NAT gateway removes its state.

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