I have an application running at port 9001 in the private EC2 instance.
I have a web server running in the public subnet. The subnets and the routeing table with IGW and NAT Gateways are set up properly.
I have security groups defined for each instance.
Web Server SG:
App server SG:
Inbound: Allowed all traffic from web Server SG
The application is listing on port 9001. So Do I need to explicitly mention port 9001 in the Web server SG and then the Application server will send the traffic to the webserver?
Or Do I need to explicitly allow traffic from Private EC2 instances like outbound rules?