This dialog allows you to edit the rules for a security group.
You can optionally create one or more rules for the security group. A rule grants a specified range of IP addresses inbound access to your instances for a protocol or custom port range. Rules for many of the most popular protocols are pre-defined and available for selection in the drop-down list box, or you can define your own rule.
To grant access to an IP address or range of IP addresses, select the IP Address radio button and enter a CIDR range in the text box.
To grant access to another security group, select the Other security group radio button and enter the name of the security group in the text box.