A Security group acts as a virtual firewall for your EC2 Instances.

● It decides the type of port and kind of traffic to allow.

● Security groups are active at the instance level whereas Network ACLs are

active at the subnet level.

● Security Groups can only allow but can’t deny the rules.

● The Security group is considered stateful.

● By default, in the outbound rule all traffic is allowed and needs to define the

inbound rules.