After a routine audit, a company discovers that engineering documents have been leaving the network on a particular port. The company must allow outbound traffic on this port, as it has a legitimate…

Network Access Control (NAC) primarily regulates which devices or users can connect to a network, not the content of the data they transmit once access is granted.

A web proxy primarily manages and filters web (HTTP/S) traffic, and while some advanced solutions may have content inspection capabilities, it is not the primary or most direct solution for preventing specific documents from leaving on an arbitrary port.

Data Loss Prevention (DLP) technology inspects the content of data streams to identify and prevent the unauthorized exfiltration of sensitive information, such as engineering documents, even when the underlying communication port is legitimate and open. DLP solutions allow businesses to define policies that protect specific types of data regardless of the protocol or port used for transmission, thus preventing data loss without causing service outages for legitimate traffic.

An Access Control List (ACL) would block or allow traffic based on port, protocol, or IP address, which would disrupt legitimate business use of the port and cause an outage as stated in the problem.