Managing security groups

Security groups can be managed using the Neutron CLI or the Horizon dashboard. From within the Neutron command-line client, a number of commands can be used to manage security groups, including:

• security-group-create

• security-group-delete

• security-group-list

• security-group-rule-create

• security-group-rule-delete

• security-group-rule-list

• security-group-rule-show

• security-group-show

• security-group-update

From the Horizon dashboard, security groups and rules are managed from the Compute | Access & Security panel.

Using CIDR to control traffic

Understanding how to properly subnet networks using the Classless Inter-Domain Routing (CIDR) notation is important for controlling access to instances. Using the wrong CIDR notation in a security group rule can expose your application and your environment to the Bad Guys™, a situation we'd like to prevent.

The following are some examples of networks using CIDR notation:

• 0.0.0.0/0 – This would allow traffic from all IP...