Security Group & Classis

 Introduction to security groups

• Security Groupes are fundamental to network security in AWS
• They control how traffic is allowed into or out of our EC2 instances
• Security groups only contain allowed group 
• Security group rules can be referenced by IP or by the security group.

What is Security Groups

• Security group acting as a firewall on Ec2 instances
• They regulate
• Access to port 
• Authorized IP range -IPv4 and IPv6
• Control of Inbound network(from other to the instance)
• Control of the outbound network(from instance to other)

Good to know about the security group

• Can be attached to multiple instances 
• Locked down to a region /VPC combination 
• Dows live outside the EC2 - if traffic is blocked the EC2 instance won't see 
• It's good to maintain one separate security group for SSH access
• if your application is accessible (timeout issue), then it's a security group issue 
• if your application gives a "connection refused" error, then it's an application error or it's not launched
• All inbound traffic is blocked by default

Classic Port to know (AWS Exam perspective)

• 22 - SSH (Secure Shell) - log into a Linux instance
• 21 - FTP (File transfer protocol) -upload files into a file share
• 22 - (Secure File transfer protocol) Upload files using SSH
• 80 - HTTP - access unsecured website
• 443 - HTTPS - assess secured website
• 3389 - RDP (Remort desktop protocol) Log into a Windows instance