On Trusted Extensions gateways, label range checks are performed in certain cases. A Trusted Extensions system that is routing a packet between two unlabeled hosts compares the default label of the source host to the default label of the destination host. When the unlabeled hosts share a default label, the packet is routed.
Each gateway maintains a list of routes to all destinations. Standard Oracle Solaris routing makes choices to optimize the route. Trusted Extensions provides additional software to check security requirements that apply to the route choices. The Oracle Solaris choices that do not satisfy security requirements are skipped.