802.1X is a network access control protocol that provides an authentication mechanism to devices trying to connect to a LAN or WLAN. It supports the use of certificates for authentication, can quarantine unapproved devices, and ensures that only approved and updated devices can access network resources. This protocol best meets the requirements of securing both wired and wireless networks with internal certificates.
References = CompTIA Security+ SY0-701 study materials, particularly in the domain of network security and authentication protocols.