Circuit-level gateway: Difference between revisions

Revision as of 18:53, 25 March 2019

Revision as of 03:36, 12 February 2020

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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. Firewall technology supervises TCP handshaking among packets to confirm a session is genuine. Firewall traffic is cleaned based on particular session rules and may be controlled to acknowledged computers only. Circuit-level firewalls conceal the details of the protected network from the external traffic, which is helpful for interdicting access to impostors. But circuit-level firewalls do not clean entity packets. Circuit-level gateways are relatively inexpensive and have the advantage of hiding information about the private network they protect. On the other hand, they do not filter individual packets.

==See also==