Creating an NACL for the public subnet

To create an NACL for the public subnet, follow these steps:

1. Navigate to the VPC service within the Management Console.
2. Select Network ACLs from the menu on the left and select the blue Create network ACL button.
3. Configure the NACL as shown in the following screenshot by selecting your VPC:

4. Now select the newly created NACL in the list that appears and it will display its configuration at the bottom of the screen.
5. Select the Inbound Rules tab. By default, a newly created NACL will DENY all traffic: 

6. Select Edit inbound rules and configure the NACL as shown here:

7. Click Create. By default, an explicit DENY will be added at the bottom of the NACL when you click Create, as shown here:

8. Select the Outbound Rules tab and configure the outbound rules as shown here. Once done, select Create:

9. Much like the route tables, we now need to associate this NACL with a subnet. Select the Subnet Associations tab | Edit...