AWS Security Group

Security Group #

A security group acts as a virtual firewall that controls inbound and outbound traffic for your instance.

When you launch an instance in a VPC, you can assign the instance to a maximum of five security groups.

Security groups operate at the instance level, not the subnet level, so each instance in a subnet in your VPC can be assigned to a different set of security groups.

If you don't specify a particular group when you launch an instance, the instance is automatically assigned to your VPC's default security group.

Features #

• Security Device
  • A service that acts as a firewall alongside Network Access Lists (NACLs).
• Port Allowance
  • You can specify the Port and Source through which traffic can pass.
  • Denial is not possible -> Possible with NACLs
• Instance-level
  • One or more SGs can be configured for a single instance.
  • NACLs operate at the subnet level.
  • Configured instances are subject to all rules of the configured SGs.

• Filters using all configured rules.
  • In the case of NACLs, filtering occurs in the order of applied rules.
• Stateful
  • Traffic that enters via Inbound can exit without any additional Outbound configuration.
  • NACLs are Stateless.