Re: [lwip-users] lwIP - PPP from windows machine

[Sylvain Rochet]

Hi Anand,

On Thu, Sep 29, 2016 at 08:56:34PM +0530, anand arjunan wrote:
> 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.


> 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.


> 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

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