[lwip-users] lwIP - PPP from windows machine

Sylvain Rochet

2016-10-01 11:00:58 UTC

Hi Anand,

Post by anand arjunan
Hi,
I am using PPP (from Windows contribution) of lwIP implementation and
trying to establish a PPP dial-up connection form my windows machine
through iridium modem using a *serial (RS232) *connection between them.
After all initialization, LCP and NCP negotiations, the LWIP debug
statements show that I am getting a new local and the remote ip address,
and the PPP connection is successful.
Though I have got a new local IP through my LWIP client, I don't know where
to set this IP in my PC as I am using a serial connection to the modem
(PPPoS).

This does not make sense, the PPP interface lives into the lwIP network
stack currently running in a user land process, therefore it shares
nothing with your OS network stack.

Post by anand arjunan
How am I supposed to proceed after this if I want to transfer a file
through ftp to the remote server?

Basically, you have to write an app inside your lwIP process to do that.

Post by anand arjunan
Instead of using my LWIP client, when I use Windows Dial-up feature using
19200 bps standard modem, the new local ip is automatically set to the PPP
dial-up network connection that I used to dial in.How do I simulate this
behavior ?

You can't per se, but if you control both ends you can use IP routing
instead. I don't know much of the win32 port but I suppose there is a
tun/tap-like interface support allowing you to setup a virtual Ethernet
channel between the lwIP stack and your OS stack, then you only have to
use IP routing between the PPP interface and the Ethernet interface in
lwIP. You obviously need to control both ends to setup the necessary
routes into their routing table, lwIP does not support SNAT as a
workaround for this requirement.

Anyway, win32 and unix ports are mostly meant to be used for test and
debug purposes of the lwIP stack, they can't be used as a replacement
for your OS stack.

Sylvain