About Domain, Host, and Port Labels : About domain labels
  
About domain labels
Domain labels enable you to create logical groupings of domains that have similar configuration characteristics. Wildcards are allowed, as are host labels. Be aware of these dependencies:
They are compatible with autodiscover, passthrough, and fixed-target (not packet mode) in-path rules. They are not compatible with IPv6 and connection forwarding and QoS rules
They don’t replace the destination IP address. The in-path rule still sets the destination using IP and subnet, or uses a port, port label, or host label. The in-path rule matches the IP addresses and ports first, and then matches the domain label second. The rule must match both the destination and the domain label.
They apply only to HTTP and HTTPS traffic. Therefore, when you add a domain label to an in-path rule and set the destination port to All, the in-path rule defaults to ports HTTP (80) and HTTPS (443) for optimization. To specify another port or port range, use the Specific Port option instead of All Ports.
A fixed-target rule with a domain label match followed by an auto-discover rule will not use autodiscovery but will instead pass through the traffic. This happens because the matching SYN packet for a fixed-target rule with a domain-label isn’t sent with a probe.
A domain can appear in multiple domain labels. You can create up to 63 unique domain labels.
About Domain, Host, and Port Labels
Domain labels and cloud acceleration
About domain label settings
Domain labels and cloud acceleration
When you add a domain label to an in-path rule that has cloud acceleration enabled, the system passes through connections to the subscribed platform. However, you could add in-path rules so that other appliances in the network optimize cloud connections.
Create an in-path rule with Cloud Acceleration set to Auto and specify the SaaS Application host label.
Place rules with domain labels lower than cloud acceleration rules in your rule list so the cloud rules are matched first.
About domain labels
About domain label settings