Which one of the following is a circuit level application gateway and works independent of any
supported TCP/IP application protocol?

A.
SOCK-et-S (SOCKS)

B.
Common Information Model (CIM)

C.
Secure Multipurpose Internet Mail Extension (S/MIME)

D.
Generic Security Service Application Programming Interface (GSS-API)

Explanation:
“Socks Proxy Server Characteristics
Circuit-level proxy server
Requires clients to be SOCKS-fied with SOCKS client software
Mainly used for outbound Internet access and virtual private network (VPN) functionality
Can be resource-intensive
Provides authentication and encryption features to other VPN protocols, but not considered a
traditional VPN protocol”
Pg. 422 Shon Harris CISSP All-In-One Certification Exam Guide
Reference:
The SOCKS is an example of a circuit-level proxy gateway that provides a secure channel
between two computers. pg. 379 Shon Harris CISSP