You have an Amazon Elastic Cloud Compute (EC2) security group with several running EC2 instances. You change the security group rules to allow inbound traffic on a new port and protocol, and launch several new instances in the same security group. The new rules apply:
- Immediately to the new instances, but old instances must be stopped and restarted before the new rules apply.
- Immediately to the new instances only.
- To all instances, but it may take several minutes for old instances to see the changes.
- Immediately to all instances in the security group
Security group rules and the changes in the rules are applied immediately to all (past and future) the instances in that security group.