circuit layer gateway (CLG)

The Circuit Layer Gateway (CLG) acts as a proxy server between the local network( LAN) and the Internet. It has filtering mechanisms that check the connection modalities between the computer and the network and allow only those data packets from the Internet to pass that have been requested by the local network.

Circuit Layer Gateways identify malware and monitor the initiation of sessions and TCP handshakes established between the local and remote hosts. In doing so, they verify that the session is legitimate and the communicating system is trustworthy. The transmitted data packets are not examined by CLG gateways. Therefore, circuit level gateways should be used in combination with other systems such as with packet filtering DPI firewalls or with content filters.