Advantage :
* A circuit-level gateway acts as a proxy for hiding the internal host from the serving host.
* It avoids the filtering of individual packets.
* These gateways are inexpensive.
* Address schemes can easily develop.
* Simple to implement.
* Every application does not require a separate proxy server.
Disadvantage :
* Circuit-level Gateway does not filter the individual packets
* Frequent updates are required
* Within the firewall, it does not offer protection against data leakage from devices.
* For using Circuit level gateways the TCP/IP stacks are mandatory to be modified by the vendor.
