For work I was given a modem, which they wanted me to hook up directly to my home internet. However, I live in a town home and do not have direct access to it. Instead I have to use a port that I have in my wall. When I plug my modem into the wall the VPN does not light on the modem, which I assume is because I have blocked access as we need to register all our devices using the MAC address. The modem I have is a Cisco 881. Is there any way to find the MAC address if not listed on the device itself?