With the Lindy RJ-45 Port Blocker, you can quickly block open network ports and easily prevent users from connecting cables, devices or inserting foreign objects without permission. This helps protect against unauthorized access to a network or system, as well as preventing unintentional or malicious damage to ports. It can also act as a visual cue, showing inactive or disconnected ports. The semi-permanent RJ-45 Port Blocker is made up of a molded plastic blocking cap that plugs securely into the RJ-45 port with a special insertion key.