I did a load test for NAT Gateway in AWS. I reached a much lower requests-limit than described in docs. According to the docs the Nat is supposed to support ~900 requests per second, but with my configuration, I saw that ~0.04% of the requests are untreated when running ~300 requests per second.

I run node.js app using ECS cluster, and have the ability to configure requests per second. The NAT is working fine around 1 minute, and later my app starts to get timeouts for few requests.

AWS does not allow access to such machines, and the cloudwatch metrics seem fine.

In general, I am looking for a static ip solution that will withstand high loads. Does anyone here has experienced something similar?