Amazon EC2 Security Groups

Question

Can someone tell me what does the following command do with respect to the Amazon EC2 security groups?

ec2-create-group CreateSecurityGroup

Answer 1

It creates a new security group for use with your account. A Security group is just like a firewall, it controls the traffic in and out of your instance. In AWS terms, the inbound and outbound traffic. The command mentioned is pretty straight forward, it says create security group, and does the same. Moving along, once your security group is created, you can add different rules in it. For example, you have an RDS instance, to access it, you have to add the public IP address of the machine from which you want access the instance  in its security group.