A PortShield interface is a virtual interface with a set of ports, including ports on SonicWall Switches or other supported external switches assigned to it. PortShield architecture enables you to configure some or all of the LAN ports into separate security contexts, providing protection not only from the WAN and DMZ, but between devices inside your network as well. In effect, each context has its own wire-speed PortShield that enjoys the protection of a dedicated, deep packet inspection security appliance.
You can configure PortShield interfaces on the NETWORK | System > PortShield Groups pages.