Security Groups

Security Groups are the fundamental of network security in AWS

 

They control how traffic is allowed into or out of our EC2 Machines

 

It is the most fundamental skill to learn to troubleshoot networking issues

 

Security groups are acting as a "firewall" on EC2 instances

 

They regulate:

- Access to Ports

- Authorised IP ranges - IPv4 and IPv6 

- Control of inbound network (from other to the instance)

- Control of outbound netwokr (from the instance to other)

Security Groups Diagram

 

- Can be attached to multiple instances

- Locked down to a region /VPC combination

- Does live "outside" the EC2 - if traffic is blocked the EC2 instance won't see it

- It's good to maintain one separate security group for SSH access

- If your application is not accessible (time out), then it's a security group issue

- If your application gives "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 authorised by default 

 

Referencint other security groups Diagram