About Domain, Host, and Port Labels
Labels help to streamline configuration tasks. You can group many items under a single label so that you can enter just the label when configuring a feature that uses those items rather than individually entering each item.
For example, let’s say you want to create an in-path rule for all Office365 traffic flowing through the appliance. Instead of creating a separate rule for each application, you could define a domain label named, say, Office365 to include all domains related to those applications. Then, you could create a single in-path rule, applying the label to it.
Label names are not case-sensitive, but rule-matching is. Names can be any alphanumeric string up to 64 characters long. The underscore ( _ ) and the hyphen ( - ) are supported. Other special characters and spaces are not supported. You can enter the same item in multiple labels.
IPv6 is not supported. You cannot delete in-use labels.
Labels are compatible with autodiscover, passthrough, and fixed-target (not packet mode) in-path rules.