A security group defines which ports are open to allow incoming or outgoing connections to a server within a network. Security groups essentially act as firewalls in the cloud. They are designed to control who can communicate (i.e., initiate communication) with a server.
Security groups give you a flexible way to restrict server access, allowing you to set restrictions specific to particular protocols, ports, IP addresses, or combinations of these. Permissions defined in a security group are additive in nature; so, if a server has two security groups where one group has port 80 open and the other group has port 80 closed, port 80 will be open (not closed) on the server.
© 2006-2014 RightScale, Inc. All rights reserved.
RightScale is a registered trademark of RightScale, Inc. All other products and services may be trademarks or servicemarks of their respective owners.