Listening socket over PAN
Hello!
We′re developing an application for a Windows Mobile 5 device which acts as both a client and a server.
We′ve tested the application with a pocketpc device (windows mobile 2003), with built-in GPRS, and that worked fine. However, now we′re trying to run it with a Windows Mobile 5 device coupled with a mobile phone, and have encountered some serious problems. the client-part can send data without problems, but the listening socket won′t receive anything.
We′ve tried with DUN and PAN (Personal Area Network), but none of it has worked.
One problem (hopefully the only one, but that′s by no means certain), is that when connected with PAN, the mobile phone reports one IP externally, and the PDA reports another internally, which led us to assume that the mobile phone acts like a NAT-router, giving internal addresses to all devices hooked up to it. So, the question is: is it possible to use some kind of port forwarding when listening to sockets on the PDA?
Answers, or suggestions to where we should turn would be highly appreciated.
Henrik
[1077 byte] By [
henke] at [2008-1-9]
I would be quite surprised if that would actually work with GPRS. It usually:
- Only allows for outgoing connections.
- Uses private IPs not visible anywhere.
- Commonly limits outgoing connections to selected ports/protocols (e.g. HTTP and POP3).
- Sometimes only works through carrier's proxy.
Contact your carrier for details on what you can and cannot do on particular network.
To make sure it’s not a problem with your application test on a real network, e.g. Wi-Fi.
Thank you for your reply.
However, as I said before, our application worked very well with a PDA with integrated GPRS (a QTEK 2020, which uses windows mobile 2003), so obviously the operator allows these settings.
Second, which I should have said before, is that we tested setting up the QTEK with an external mobile phone instead using of its integrated GPRS capabilities, connected them via PAN as well, and then it worked! So obviously, there has to be some way of forwarding the data for a port from the phone to the PDA. A friend of mine told me it COULD be that the QTEK and the phone both supported some kind of firewall extensions, thus allowing automatic forwarding, but he didn′t really know.
Furher help greatly appreciated,
Henrik
