The IE RJ45 Port Lock enables mechanical closing of unused RJ45 ports on network components and data terminal equipment. The RJ45 Port Lock has the shape of an RJ45 connector, and when used in an RJ45 socket it prevents the unintentional plugging in of RJ45 cables. The latch of the RJ45 Port Lock is blocked with the integrated lock that can only be locked and unlocked with a mechanical key. The Port Lock can thus only be removed after unlocking with a mechanical key. The RJ45 Port Lock can be used on devices with and without retaining collars.