By checking content at application level, application gateways are a supplement to the packet-filter address validation and stateful-packet-inspection connection monitoring. As a rule, the high demands on hardware performance require the application gateway to run on a separate computer. This computer is located between the local network and the Internet. Seen from either direction, this computer is the only way to exchange data with the other network. There is no direct connection between the two networks, just to the application gateway.