First off, make sure you are not using a WinModem.
You must have a "true" modem that has a selection for IRQ, and COM port. Set these to whatever IRQ and COM port that you set on the card. For example, let's say I've installed a modem with the IRQ 3, Com 2.
In Linux, you will then have to add a symbolic link using the commands below. Depending upon which version (distribution) of Linux, you may have to use a different device name.
cd /dev
ln -s /dev/ttyS1 modem
This assumes that you are using the settings that I have shown above (COM 2).
Some distributions (such as Mandrake) have a decent setup program that will configure most of the options needed.
Make sure that you set the proper permissions for the ttySx device also.
chmod a+rwx ttySx (where x is 0 .. 3)
Most ISPs have a listing of the parameters needed to connect to their servers. I'd recommend checking with them for the modifications to the ppp files... I use Mindspring at home with my small network. They have a good listing on their TechPages that explains the options that they require. This assumes that you are using the standard ppp programs. If you use KPPP (or something similar), the procedures will be a little different.
I have not found a distribution yet that has IP Masquerading set up by default (and I've looked at Mandrake, Corel, Caldera, and RedHat). This is probably the best method I've seen of accomplishing this. This involves recompiling the kernel with severalnew options.
I found a good write up on this on www.linuxnewbie.org. From there, go to the NHF section and look on the right for a link to "compiling". From there, look for a listing about Compiling a Kernel and a listing for IP Masquerading.
Some good sites for info that I've seen...
www.linux.com
www.linuxnewbie.org
I hope this helps
