I started two EC2 instances in an Elastic Beanstalk autoscaling group in a VPC. The app on these EC2 instances needs to connect to a third party service that uses an IP address whitelist to allow access. So I'm using NAT Gateway to have static IPs so they can be added to the whitelist. The third party have already given access to the IPs from the two NAT Gateways I have configured at aws console. But I cant connect yet. On the development environment which accepts any IP connection the app is running ok.
There is a chance that I'm using wrong IP? Which command can I use to know which IP my app is getting in the internet? I did traceroute from the server to the third party service and it didn't showed the NAT Gatewa IP, is this right?