Modem speed & IP address differences?

[Kaizoku ChaosStar]

i do have a USB modem, that's pretty much like the one, brourke pictured in his PC-DC server tutorial, not to use in ubuntu because it's too weak. In Ubuntu I recorded a speed of 460800 bps on it, during modem detection in ubuntu. I see that most people get 115200 bps as max.

So the question is why is it still so, that I get the "NO CARRIER" message each time I'm trying to initiate the final connection?
I get an "A_FAILED" and "caller=none" along with some other stuff.

I would also like to know which IP address the ryochan7 tutorial is referring to at the part in the "options.(Interface)". My primary DNS is 193.213.112.4. I got that down in the first part, but my standard gateway address is 10.0.0.138 and main IP address is 10.0.0.4 (modem and router in one). All I need to know is which of the addresses to look at when choosing a proxy IP and an IP for the Dreamcast under that file.

Please help.