Security Groups

• A security group acts as a virtual firewall to control inbound and outbound traffic for your Elastic Network Interfaces (ENIs).

• Security groups are applied at the ENI level, not the subnet level.

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⚙️ Key Features

• Inbound & Outbound Traffic:

  • Inbound: Controls the traffic coming into an ENI.

  • Outbound: Controls the traffic leaving an ENI.

• Stateful:

  • If you allow incoming traffic, the response traffic is automatically allowed, regardless of outbound rules.

• Applies to ENIs:

  • Security groups are associated with ENIs, meaning they can be applied to individual network interfaces in your instances.

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🧠 Quick Summary

Feature	Description
Purpose	Control inbound and outbound traffic at the ENI level
Applied To	Elastic Network Interfaces (ENIs)
Stateful Nature	Automatically allows return traffic for approved inbound traffic