4. Security Considerations

If you have only one modem for all your hosts in your local area network, there is probably no reason to worry about security here. However, if any one or more of the hosts in your LAN are connected to the Internet by other means than using the modem we have just setup as a modem server, then security considerations are required, otherwise anybody can do a telnet your_host modem and dial out long distance or even international calls at will.

I suggest to install and configure tcp-wrappers in order to protect the modem server against unauthorized access.