As the title says, I’ll create two web servers in a private subnet, put an Application Load Balancer in front and protect the content with Web Application Firewall (WAF). In addition, I’ll create a bastion host so I can access the web servers using SSH. Web Servers are not reachable from the Internet.
First thing to do is to create an Elastic IP for the NAT gateway. NAT gateway is needed if you want to give the Web Servers Internet access so they can be patched. Go to Elastic IPs under Network & Security in EC2 menu and click on Allocate Elastic IP address in the top right corner. Accept the defaults and click Allocate.
We’ll create a VPC with two public and two private subnets. Minimum two public subnets are needed for the Application Load Balancer. You can’t create an ALB with one public subnet.
This is just a sample. The original blog post is here.