How Can I Check the Network Configuration of a Backend Server?

1. On the server details page, view the security group.
2. Check whether the security group rules allow access from the corresponding IP address range.
   • Dedicated load balancers: Check whether the security group of the backend server has inbound rules to allow traffic from the VPC where the load balancer works. If traffic is not allowed, add an inbound rule to allow traffic from the VPC to the backend server.
   

   • Load balancers: If IP as a Backend is not enabled for a load balancer that has a TCP or UDP listener, there is no need to configure security group rules and Network ACL rules to allow traffic from the backend subnet where the load balancer is deployed to the backend servers.

In the navigation pane of the VPC console, choose Access Control > Network ACLs and check whether the subnet allows traffic.