I'm in the process of switching from conventional to internet phone service. I'm using a Linksys router/phone adapter, model SPA2102. While configuring the router, I learned of the IVRM (Interactive Voice Response Menu) feature, which enables the user configure the router-adapter with a telephone. I'm very concerned with the security implications of this "feature" as it can be used to change any or all of the settings, including a full factory reset and changing the password.
This is copied from the manual. IMO, this seriously degrades the strength of a password.
Click to view attachment
With attacks on routers becoming more common, I opted to install the router behind Smoothwall so I could control and monitor its traffic. I'm questioning the security of the IVRM feature, concerned that it could be used to bypass Smoothwall using traffic that's necessary for normal operations. I'd like to completely disable it but I don't see any way to do this. The manuals are no help. Anybody know how to shut off this "feature"?

At present, the router/adapter is installed between Smoothwall and my PC. When I assembled the PC with Smoothwall, I only installed 2 network cards. Didn't plan on hosting a website, adding a server, etc, so I didn't set up a DMZ. Would I be better off adding a 3rd network card as a DMZ and hooking the router-adapter to it? Internet phone service is new to me so I'm open to suggestions as to the best way to set this up.
Rick

If you can't disable the feature, just make the password something insanely long and difficult. Then change it (staying insanely long and difficult) whenever you change your other passwords.

So far, no success with disabling IVRM. For now, I've moved the phone adapter/router back in front of the firewall until I'm convinced that its configuration can't be altered from the net or via the phone. Unless there's another menu or method of configuration I'm not seeing, there doesn't seem to be any way to limit what can be changed or accessed via this IVRM.
Rick