ANS-C01 · Question #87
A network engineer deploys an application in a private subnet in a VPC that connects to many external video feed providers using RTMP over the internet. A NAT gateway has been deployed in a public…
The correct answer is A. The NAT gateway does not support fragmented packets. Some of your TCP connections from instances in a private subnet to a specific destination through a NAT gateway are successful, but some are failing or timing out. The cause of this problem might be one of the following: The destination endpoint is responding with fragmented…
Question
A network engineer deploys an application in a private subnet in a VPC that connects to many external video feed providers using RTMP over the internet. A NAT gateway has been deployed in a public subnet and is working as expected. From the Amazon EC2 instance, the application is able to connect to all feed providers except one, which hangs when connecting. Manually testing a connection from an Amazon EC2 instance in the public subnet to the problem feed indicates that the feed works as expected. What is causing this issue?
Options
- AThe NAT gateway does not support fragmented packets.
- BThe internet gateway only supports an MTU of 1500 bytes.
- CAn Amazon EC2 instance expects to communicate with an MTU of 9001.
- DThe security group on the instances does not allow PMTUD.
How the community answered
(25 responses)- A64% (16)
- B4% (1)
- C20% (5)
- D12% (3)
Explanation
Some of your TCP connections from instances in a private subnet to a specific destination through a NAT gateway are successful, but some are failing or timing out. The cause of this problem might be one of the following: The destination endpoint is responding with fragmented TCP packets. A NAT gateway currently does not support IP fragmentation for https://docs.aws.amazon.com/vpc/latest/userguide/nat-gateway-troubleshooting.html
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