PPP Dial-up services for
Coyote Linux and Brazil Firewall

It seems that configuring Coyote Linux/Brazil Firewall to use dial-up services (PPP) is a little harder to do then the high-speed connections. The questions are usually the same or similar. Here are some guidelines that may help you accomplish this task. I will update these pages as I see more solutions to problems.

There are two types of serial modems: external (attached to the outside of your computer via a cable) and internal (a card inside your computer). If you have a PCI card, there is a good chance your "modem" is NOT a real modem but a WinModem® and requires software installed in Microsoft Windows®. Hence the name WinModem. End of project. You are out of luck.If you feel courageous you may try your hand at installing a LinModem driver. See linmodems.org. You can also search Google for linmodems.

Ensure that your configuration is set like the type below that matches your situation.

External Modems:

• Port 1 and 2 enabled in BIOS at standard I/O addresses and IRQs (you can disable one later).
  Port 1 = COM1 = ttyS0 = I/O 3F8 IRQ 4
  Port 2 = COM2 = ttyS1 = I/O 2F8 IRQ 3
  Some BIOS settings let you set both; others just the I/O address.
• No other ISA card, like a NIC, that uses these resources.
• A known good modem set to default factory settings for hardware flow control (switches and software). This is usually AT&F1 (USRobotics/3Com) or AT&F (generic). Find this out.
• A known good serial cable connected between the modem and the communication port of the PC.

Internal Modem:

• Port 1 and 2 disabled in BIOS. (you can enable one later)
• Use COM1 or COM2 as there is no real standard for COM3/COM4 (for I/O, IRQ) whereas the standard for COM1 and COM2 was established in 1981 when IBM invented the PC.
  Check the card. There should be jumpers that set the modem.
• No other ISA card, like a NIC, that uses these resources.

Troubleshooting

When booting Brazil Firewall/Coyote Linux, something like the following should appear in the syslog. If you don't get a line(s) like the one(s) highlighted, your configuration will never work. Syslog is available via the Webadmin tool. Shortly after boot-up this is also on the console. You can scroll up or down using Shift-PageUp or Shift-PageDn respectively.

Based upon Swansea University Computer Society NET3.039
Initializing RT netlink socket
Starting kswapd
pty: 256 Unix98 ptys configured
Serial driver version 5.05c (2001-07-08) with MANY_PORTS SHARE_IRQ SERIAL_PCI enabled
ttyS00 at 0x03f8 (irq = 4) is a 16550A
ttyS01 at 0x02f8 (irq = 3) is a 16550A

Another big problem is wrong parameters in A:\config\coyote.cfg that was created by the Windows Wizard. These are: PPP_INITSTR= and PPP_PORTSPEED= which is missing.
They should be set as follows:
PPP_INITSTR=ATZ or PPP_INITSTR='AT&FS11=55'  Notice the single quotes.
PPP_PORTSPEED=115200    very important  (fixed in latest version)

A common problem with internal modems in old PCs is resource conflicts where 2 cards are set to the same IRQ or I/O address or COM ports not disabled in the BIOS.

External modems are affected by COM ports being disabled in the BIOS. When booting the Brazil Firewall/Coyote Linux PC, lights on the powered on modem should flash at some time. If they don't there is a problem with the internal or external cabling. The COM port on the motherboard could be dead. Try the other.

If there is no serial port support in the operating system (impossible in DOS) then no modem will work. The only way I can see this is if you generate the floppy disk for PPPoE (high speed ADSL) and try to connect via a modem. In this case I am asking myself "What are you doing?"

Here is quick test that verifies what COM port the modem is set to. This will work for internal or external.
We will send a simple command to bring up a dial tone. Or listen closely and you will hear a click as it tries to get the line. Whichever command works tells you the port number.
Connect a working telephone line to the modem. (into the proper RJ11 jack)

From the console command line (Notice the uppercase S. It makes a difference.)
echo ATD >ttyS0    port 1 is active
echo ATD >ttyS1    port 2 is active

From the DOS command line (Case is unimportant here. COM1: = Com1: = coM1: = cOm1:)
echo ATD >COM1:     port 1 is active
echo ATD >COM2:     port 2 is active

Ok! Now that you have resolved which port is active, you want to set your modem to the factory defaults for hardware flow control as per your modem documentation. Use the format of the command above that worked and replace ATD with AT&F1&W (or whatever your documentation says).

PPP diagnostics part 1 plus details of a tiny program that allows you to talk to the modem and get replies.
A PPP debug diagnostics session is presented in part 2.