Added firewall rules to block external traffic on os_compat instances

envs/os_compatibility/README.md

@@ -60,6 +60,7 @@ A quick reference for usernames on different machines (if in doubt check officia
 - Everything else: ec2-user
 
 To manually verify the machine is compatible use commands to download and execute the monkey.
+Also, add your IP to `os_compat_instance` security group.
 
 Example commands:
  - Powershell:

envs/os_compatibility/terraform/infra.tf

@@ -76,7 +76,7 @@ resource "aws_security_group" "os_compat_instance" {
     from_port   = 0
     to_port     = 0
     protocol    = "-1"
-    cidr_blocks = ["0.0.0.0/0"]
+    cidr_blocks = ["10.0.0.0/24"]
   }
 
   egress {