Mastering GitLab 12

SGs

SGs are a very important part of the security that you can use to control inbound and outbound network traffic. In traditional networks, you would usually place firewall appliances between networks or subnets to control network flows. In AWS, an SG takes on this role. Besides not being a physical device, the other difference is that SGs are not specified on the subnet level. In a VPC, you assign EC2 instances to these security groups, so the security rules are on an instance level. There can be a maximum of five security groups assigned. If you don't assign anything, an instance will get the default security group for the VPC.