Security Group

• It is a virtual firewall works at egress network interface or instance level.

• Security group work at instance level.

• Up to five security group per EC2 instance can be attached.

• Can only have a permit rules, don't have deny rules.

• It is stateful in nature, if a traffic is allowed in inbound rules it would be automatically into outbound rules but not vice versa.

Stateful is nothing but all rules are evaluated before decision to allow traffic

• By default anything aside from permit or mentioned inbound or outbound rule will be considered denied.

• By default all traffic is denied.

• Security group have rules that control inbound and outbound instance traffic