Trouble with tcpListener in CF

[bonedoc]

I am trying to do a file transfer between my desktop and my Treo in CF. It works perfect when plugged to the USB. When I unplug it and communicate through the Treo internet service, it properly sends signals to my computer using a DNS address and Port number. Once it sends it's request and starts listening for a reply, and it recieves nothing. It is listening, by my PC says that there was not response from my Treo. Does anyone know what would cause this? I am using DNS for the Treo and PC. Do you think the Sprint DNS could be slow and timing it out?

 

[JohnH]

This may be obvious for someone knowing a "Treo", but I see it like this: is the connection LAN or Internet? (ie local area or public area) These are different connection environments, but for both you have to check if the listener have a firewall that allows incoming connection. It sounds as you are switching between different network adapters also, which does matter for the private IP of the listener.

 

[bonedoc]

Hey John, It works great when it is plugged into the computer with USB, which throws it into the LAN. When disconnected, it switches to internet. When I use internet and send a connection request(using my PC DNS and a port) from the Treo to the PC, it accepts and transmits. Well, the other way around does not work with internet (it does with the LAN). When the PC requests a TCP connection, it times out/fails to respond. So, my 2 thoughts are:

1.Sprint has a slow DNS that times out.
2.There is a firewall in the Treo that needs to be open....which I cannot seem to find for the life of me.

To make things a little more complicated, the IP of the Treo is IPv6 when on the net. Maybe the TCP cannot connect to this format? I doubt that this is the case right now, because I set DNS service up with my Treo, so DNS should resolve my TCP request for me..I think.

 

[JohnH]

Maybe the TCP cannot connect to this format?

IPv6 is a different protocol than regular IP(v4). When using v6 all networking hardware and software equipment along the way must support this protocol. If only one does not the chain breaks. IPv6 is not very common yet. Windows Vista is the first Windows OS that supports this by default. With Windows XP you can easily enable it by adding that protocol to the network adapter, but it does not by default (meaning most poeple never touch this configuration and not using it). As for the internet I cannot tell, I read that much upgrading has been done to ready this revolutionary web change, but I also read NAT security that is very common currently conflicts this.

.Net sockets supports IPv6 throughout. (from .Net 1.1 onwards, CF from 2.0)