Using /etc/ppp/options.ttyname on a Dial-in Server

For a dial-up link, you might choose to create individual /etc/ppp/options.ttyname files for every serial port on a dial-in server with a modem attached. Typical options include the following:

• IP address required by the dial-in server

  Set this option if you require incoming callers on serial port ttyname to use a particular IP address. Your address space might have a limited number of IP addresses that are available for PPP in comparison to the number of potential callers. In this situation, consider assigning an IP address to each serial interface that is used for PPP on the dial-in server. This assignment implements dynamic addressing for PPP.

• asyncmap map-value

  The asyncmap option maps control characters that cannot be received over the serial line by the particular modem or ISDN TA. When the xonxoff option is used, pppd automatically sets an asyncmap of 0xa0000.

  map-value states, in hexadecimal format, the control characters that are problematic.

• init "chat -U -f /etc/ppp/mychat"

  The init option tells the modem to initialize communications over the serial line by using the information in the chat -U command. The modem uses the chat string in the file /etc/ppp/mychat.

• Security parameters that are listed in the pppd(1m) man page