A host group is a collection of: DNS domain names, DNS host names, IP addresses, IP ranges, MAC addresses, or subnets that are grouped under one name. The purpose of host groups is to eliminate the retyping of host addresses and names. For example, you can add multiple IP addresses one at a time to a firewall rule. Or, you can add multiple IP addresses to a host group, and then add the group to the firewall rule.
As you incorporate host groups, you must describe where the groups are used. If you decide later to delete a host group, you must first remove the host group from all the firewall rules that reference the group.
When you add a host group, it appears at the bottom of the Hosts list. You can access the Hosts list from the Host field in a firewall rule.
To add host groups
In the console, click Policies.
Expand Policy Components, and then click Host Groups.
Under Tasks, click Add a Host Group.
In the Host Group dialog box, type a name, and then click Add.
In the Host dialog box, in the Type drop-down list, select a host.
Type the appropriate information for each host type.