Securing Your AWS Environment: Security Groups & NACL - Day 6 Recap

Hey everyone! 🔒

I'm back with another update on my AWS journey, and today's focus was on AWS Security Groups and Network Access Control Lists (NACLs). In Day 6 of Abhishek Verramalla's AWS playlist, we dove deep into how to secure your AWS resources with these two powerful tools. Here’s what I learned.

Video 6: AWS Security Groups & NACL

Key Topics Covered:

1. What are Security Groups?

   • Security Groups act as virtual firewalls that control inbound and outbound traffic to AWS resources like EC2 instances.

   • They operate at the instance level and allow traffic based on rules you define (no deny rules).

   • We learned that security groups are stateful, meaning that if traffic is allowed in one direction (e.g., inbound), the return traffic is automatically allowed, even if there isn’t an explicit outbound rule.

2. Creating Security Group Rules

   • Abhishek showed us how to create security groups and define rules for which types of traffic to allow or deny:

     • Inbound rules control the incoming traffic. You specify the protocol (like TCP), port range (e.g., port 80 for HTTP), and the source (IP or CIDR).

     • Outbound rules control the outgoing traffic, and we usually allow all outbound traffic unless specific restrictions are required.

   • The demo involved creating a security group that allows HTTP (port 80) and SSH (port 22) traffic only from a trusted IP range, ensuring secure access to an EC2 instance.

3. What is a Network Access Control List (NACL)?

   • NACLs (Network Access Control Lists) provide an additional layer of security by controlling traffic at the subnet level.

   • Unlike security groups, NACLs are stateless, meaning you must explicitly define both inbound and outbound rules.

     • If traffic is allowed in one direction (e.g., inbound), you also need to allow it in the other direction (outbound) for the connection to work properly.

   • NACLs also support deny rules, allowing you to block specific traffic based on your requirements.

4. Security Groups vs. NACLs

   • One of the key points Abhishek explained was the difference between security groups and NACLs:

     • Security Groups: Work at the instance level, are stateful, and don’t support deny rules (only allow rules).

     • NACLs: Work at the subnet level, are stateless, and allow both allow and deny rules.

   • Security groups are typically used for finer-grained control over specific instances, while NACLs are useful for broader control over an entire subnet of instances.

5. Hands-on: Setting Up Security Groups and NACLs

   • Abhishek walked us through a demo where we:

     • Created a security group with rules to allow HTTP and SSH traffic to an EC2 instance.

     • Configured a NACL for a VPC subnet, restricting all traffic except for specific ports.

     • Tested the configuration to see how changes in security group and NACL rules affected the traffic flow.

6. Best Practices for Securing AWS Resources

   • Abhishek shared some best practices when working with security groups and NACLs:

     • Always restrict inbound traffic as much as possible and only allow the IP addresses that need access.

     • Regularly audit your security groups and NACLs to ensure no unnecessary open ports or IP ranges are allowed.

     • Use NACLs to block malicious IPs or entire IP ranges at the subnet level, providing an extra layer of protection.

My Takeaways:

This video really helped me understand the difference between security groups and NACLs and when to use each. The stateful vs. stateless nature of these tools makes a big difference in how traffic is handled, and I now feel more confident about securing AWS resources at both the instance and subnet levels.

I especially appreciated the demo where we set up a real-world scenario with security group and NACL rules. It made everything click, from controlling traffic to securing access to critical resources.

What’s Next:

Next up, we’ll dive deeper into IAM (Identity and Access Management), where we’ll learn about managing user permissions and securing access to AWS resources. I’m excited to strengthen my understanding of AWS security!

Stay Tuned for More AWS Insights 🔐

Thanks for following along! If you’re working on securing your AWS environment or just getting started with AWS, feel free to reach out with questions. I’ll be posting more as I continue through Abhishek's AWS series!