Prevent Modem Interface Access

Dear All

I was researching in the forum, but couldn't find the specific information.
I need to prevent access from the customers into the modem config interface in order to disable administration options like set a static IP address. Just left open the diagnostics page.
One of the modems we typically use is the cisco dpc2325 but we also have Motorola and others.
Do you know some generic modem config to do this?

Thanks.