File Server: Dial-Back Access And Security

Do you know of a dial-back verification system for dialing into an AppleTalk network? I want remote access to a file server and as much security as possible for this type of access. I know of Liaison and Shiva NetModems, but I'm not sure what is available for dial-back security and user verification.
Both Liaison and Shiva NetModems offer dial-back network access as a part of the software. For address information, check the Tech Info library under "Liaison" and "Shiva NetModem."
Published Date: Feb 20, 2012