The technician should change the default administrative password FIRST to ensure the network equipment is secured against external threats on the Internet. Changing the default administrative password is a basic security measure that can help prevent unauthorized access to the network equipment. Locking all devices in a closet is a physical security measure that can help prevent theft or damage to the devices, but it does not address external threats on the Internet. Ensuring all devices are from the same manufacturer is not a security measure and does not address external threats on the Internet. Installing the latest operating system and patches is important for maintaining the security of the network equipment, but it is not the first action the technician should take1