{{Short description|Type of firewall in computing}}
A '''circuit-level gateway''' is a type of [[Firewall (networking)|firewall]].
Circuit-level gateways work at the [[session layer]] of the [[OSI model]], or as a "shim-layer" between the [[application layer]] and the [[transport layer]] of the [[TCP/IP]] stack. They monitor TCP handshaking between packets to determine whether a requested session is legitimate. Information passed to a remote computer through a circuit-level gateway appears to have originated from the gateway. Circuit-Level Firewalls applications represent the technology of next to first generation .Firewall technology supervise TCP handshaking among packets to confirm a session is genuine. Firewall traffic is cleancleaned based on particular session rules and may be controlled to acknowledged computers only. Circuit-level firewalls conceal the networkdetails of the protected itselfnetwork from the external traffic, which is helpful for contradictinginterdicting access to impostors. But Circuit-Level Firewalls don't clean entity packets. This is useful for hiding information about protected networks. Circuit level gateways are relatively inexpensive and have the advantage of hiding information about the private network they protect. On the other handHowever, they do not filter individual packets.
