An enhanced and robust connectivity PPP (Point-to-Point Protocol) implementation that is heavily used by Internet Service Providers to support networking over serial lines for Internet applications. Includes extensive modem/connectivity device support, advanced error checking and negotiation, and authorization through PAP/CHAP.

For the layered SCO PPP from Morning Star product:

• No graphical configuration utility is available.

• The local IP address of each PPP connection must be on a different subnet number than the Ethernet IP address (if there is one).

• Up to 64 concurrent sessions are supported.

• Dialback is only supported for clients calling back servers (\M in Systems chat script); SCO PPP from Morning Star does not support servers calling back clients.

• An SCO OpenServer or SCO Internet FastStart system on a local network will automatically be set up as a gateway when a PPP connection to the internet is established. SCO UnixWare systems, however, must be configured by hand to forward packets; see the SCO UnixWare documentation for configuration information.

• Connections made using SCO PPP from Morning Star will only reach a baud rate of 38400 on SCO UnixWare systems; however, SCO OpenServer systems will go as high as 115200 baud.

• Dial-in PPP connections are counted as login sessions on SCO UnixWare systems and will count towards the limits on a user license. However, PPP sessions do not count as logins on SCO OpenServer and SCO Internet FastStart systems.

• Assigning IP addresses from a pool--To configure the system to automatically select an IP address for inbound PPP connections from a pool of addresses, first define the pool and then activate IP address pool selection:
  1. Create the file /usr/lib/mstppp/IPPool with one line for each IP address you want to include in the pool of addresses.

     On each line, include three fields: local IP address, remote IP address that may connect to the local address, and netmask. For example:
     

     154.227.87.98    145.127.182.124    255.255.255.0
     

  2. On the Internet Services page of the Internet Manager, press the Network button, then press PPP Connections. Press Add New Dial-in PPP Connection or select an existing dial-in connection to modify.
     

     When the /usr/lib/mstppp/IPPool file exists, the inbound PPP connection configuration page displays a "Use IP Address Pool" checkbox. If you check this box, an IP address for the inbound connection will be chosen from available addresses listed in the IPPool file.
     

     Make sure dynamic reassignment of IP addresses is enabled on the system dialing in. (If the dialing system has an SCO Internet Manager, select the "Dynamic" checkbox when configuring the dial-out connection.)
     

• Line not dropped when active inbound PPP connection deleted--If you delete a PPP connection (with the Internet Manager) while that connection is active, the line will not be dropped, the pppd daemon will not be killed, and the /dev/tty* file will still be owned by the UID of the deleted user. To correct this, the system administrator should kill the orphaned pppd process (or reboot).

• Using PPP to connect to SCO UNIX System 3.2v4.2 or SCO Open Desktop Release 3.0--Before using SCO PPP from Morning Star to connect your SCO UnixWare system to either of these systems:
  

  SCO UNIX System V/386 Release 3.2 Version 4.2.0 with SCO TCP/IP 1.2.1
  SCO Open Desktop Release 3.0
  

  first install Support Level Supplement (SLS) net382e on that system. This will prevent intersystem PPP option negotiation problems. SLS net382e is available from:
  

  ftp://ftp.sco.com/SLS/net382e.Z

  Also download instructions and notes for the SLS from:
  

  ftp://ftp.sco.com/SLS/net382e.ltr.Z

  If you are using SCO PPP from Morning Star to connect to an SCO system running a release of SCO TCP/IP earlier than 1.2.1, add the PPP option "nolqm" to the end of the line for that the connection in these files on your SCO UnixWare system:
  

  /usr/lib/mstppp/Autostart (for outgoing connections)
  /usr/lib/mstppp/Accounts (for incoming connections)
  

  This will avoid LQM option negotiation problems.

• The pppd daemon writes to the log file /usr/adm/pppd.log using UTC (not local) time in entries. UTC (Universal Time Coordinated) is Greenwich Mean Time (GMT).

• If you use a device other than a standard serial port for a dial-in PPP connection, the error message:
  

  ioctl: Invalid argument

  may appear in /usr/lib/mstppp/Log. This is normal and does not affect PPP functionality.

• PPP dial-in connections sometimes fail during initialization, putting this error message in /usr/adm/pppd.log:
  

  pppd: Fatal system error: Can't ifconfig du1 (SIOCSIFADDR): File exists
  

  Repeating the dial-in attempt should be successful.

• If you use a PPP connection with a dynamically assigned remote IP address as your primary connection to the Internet, you must edit /etc/tcp to add the default boot-time route.

• /usr/bin/enable and /usr/bin/disable change the file owner for the specified tty to bin. This may cause the error "Connect failed: CAN'T ACCESS DEVICE" even if /usr/lib/uucp/Devices is properly configured.

• When using hardware handshaking on modems, "rtscts-crtsfl" is the pppd option you should use with the SCO serial driver. When needed, this option should be added to the entry in the /usr/lib/mstppp/Autostart file for outgoing connections, and the /usr/lib/mstppp/Accounts file for incoming connections.

  Execute the command /usr/lib/mstppp/pppd help | more for a list of all the options available with PPP.

• An enhanced serial driver is incorporated into SCO PPP from Morning Star to provide data speeds up to and including 115200bps on your standard COM1 and COM2 ports, as well as other non-intelligent serial boards listed by the mkdev serial command. However, these high serial speeds are subject to the following hardware limitations:

  -Serial ports without a 16550 UART chip are only supported at data rates up to and including 9600bps. Contact your serial board or system manufacturer to be sure that you are using a serial board with a 16550 UART.

  -Due to the rate at which interrupts can be handled and the speed at which the UART buffer is overwritten at high speeds, simultaneous data rates of 57600bps or higher are only supported on a single serial port at a time.

• If you use a PPP connection with a dynamically assigned remote IP address as your primary connection to the Internet, you must add the default boot-time route. Use the Internet Setup admin tool, in the Admin_Tools > Networking folder. See the SCO UnixWare documentation for further details.

• Incoming PPP connections to SCO UnixWare systems running SCO PPP from Morning Star may disconnect immediately; this is caused by the remote system sending PPP frames before pppd has switched the tty into raw mode. To correct this, remote systems should use passive mode when dialing in to the SCO UnixWare system.

  To use passive mode if the remote system is running SCO PPP from Morning Star, edit /usr/lib/mstppp/Autostart and add "passive" to the line that defines the link:
  

  /usr/lib/mstppp/dialout 127.0.0.2~:127.0.0.3~ passive auto exec
  /usr/lib/mstppp/exec.dialout netmask 255.255.255.0 debug 4
  

  For other PPP software, refer to the software's manual for information on passive-mode connections. If the client's PPP software does not support passive-mode connections, add a suitable delay to the chat script that is used to connect to the UnixWare system. After sending the password, have the client's chat script wait for the string "Starting PPP", then delay a few more seconds.

  For example:
  

  in:--in: <login> word: <password> PPP \d\d
  

  
  This chat script should give the SCO UnixWare system sufficient time to start up pppd before receiving any PPP frames from the client.
  
  

The SCO PPP from Morning Star User's Guide can be accessed online at http://<ServerName>:457/inethome.html on SCO OpenServer and SCO Internet FastStart systems, and at file:/usr/lib/scohelp/sephome.html on SCO UnixWare systems. PostScript files of this book are located on the CD at /mnt/ppp/ps_doc.