Firewalls & Security Groups

Summary

Controlling what network traffic is allowed in and out of a system — traditional firewalls, and cloud-native security groups/network ACLs that serve a similar purpose in AWS/GCP/Azure environments.

• 1Configure a basic firewall rule (e.g. via ufw or a cloud security group) allowing only necessary traffic.
• 2Learn the principle of least privilege applied to network access: deny by default, allow explicitly.
• 3Understand the difference between stateful and stateless firewall rules.