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Security Groups

·340 words·2 mins

Amazon Security Groups #

  • Security Groups are the fundamental of network security in AWS
  • They control how traffic is allowed in or out of our EC2 instances
  • Security Groups only contain allow rules
  • Security Groups rules can reference an IP or another Security Group
  • Security Groups are acting as a “firewall” for EC2 instances


Security Groups scope #

  • Access to Ports
  • Authorized IP ranges - IPv4 and IPv6
  • Control inbound network
  • Control outbound network

Security Groups principals #

  • Can be attached to multiple instances
  • Locked down to a region / VPC combination
  • Lives “outside” of an EC2 instance - if traffic is blocked, EC2 won’t see it
  • It’s a good practice to maintain one separate SG for SSH access
  • If application is not accessible (time out) then it’s a Security Group issue
  • If application gives a “connection refused” error then it’s an application error or it’s not launched
  • All inbound traffic is blocked by default
  • All outbound traffic is allowed by default

» Sources « #

Full YouTube Rahul’s AWS Course: https://www.youtube.com/playlist?list=PL7iMyoQPMtAN4xl6oWzafqJebfay7K8KP

» Table of contents (CLF-C02) « #

1. What is Cloud Computing2. IAM3. Budget
4. EC25. Security Groups6. Storage
7. AMI8. Scalability & High Availability9. Elastic Load Balancing
10. Auto Scaling Group11. S312. Databases
13. Other Compute Services14. Deployments15. AWS Global Infrastructure
16. Cloud Integrations17. Cloud Monitoring18. VPC
19. Security and Compliance20. Machine Learning21. Account Management and Billing
22. Advanced Identity23. Other Services24. AWS Architecting & Ecosystem
25. Preparing for AWS Practitioner exam

» Disclaimer « #

Disclaimer: Content for educational purposes only, no rights reserved.

Most of the content in this series is coming from Stephane Maarek’s Ultimate AWS Certified Cloud Practitioner CLF-C02 2025 course on Udemy.

I highly encourage you to take the Stephane’s courses as they are awesome and really help understanding the subject.

More about Stephane Maarek:

This article is just a summary and has been published to help me learning and passing the practitioner exam.