Block all the new devices connecting to the network

Hi there,

I work in an environment with over 700 assets, multiple switches (Alcatel-Lucent) and 3 different subnets.

All the assets are connected to a domain and have DHCP IPs.

I'm asked by my boss if there's a way to save the current assets connected to the network and block all the new ones, even if they're connected to the domain.

He asked if it is possible to do it via MAC address, allow the already existing ones and block the new ones.

I'm more of a HelpDesk than a Networking guy so I really need your help folks!