Router problem

[Rob123]

I have 2 routers, 1 to provide internet, and one to provide a wireless network. The wireless router can be used to handle the internet by itself, but we had already established a network when we bought the wireless, and as only 1 person uses the wireless, it would be more bother than its worth to re-do the networks.

The problem I'm having is with port forwarding. In both of the router's settings, I've forwarded the port 6112 and 4050 to my computer (192.168.0.6), with both UDP and TCP enabled. I have an app listening on port 6112, and it's able to recieve incoming calls on this port, and it was unable to before I had enabled the port forwarding. However, this is the only app which can recieve incoming calls (on either port 6112 and 4050), no other app works.

When I have tried other apps (with the working one closed down), the port appears blocked and I am unable to recieve incoming connections. I use windows firewall, and currently I have it turned off.

Why is it that only this 1 app can listen, while others cannot. (I don't mean at the same time, though)

Any help would be appreciated

[the182guy]

that is strange, how are you closing the app? if you dont close the sockets which are listening or any connections and you terminate the app it might leave the ports still bound to your sockets which are gone.

its like when you have a winsock connection and you force shutdown the computer, the other side sees the connection as still alive because the sockets were not unloaded correctly.

[Rob123]

The app that works is a game I play, which only uses port 6112. It doesn't interfere with port 4050 even when it is open, yet port 4050 still is blocked somehow. The app I made (The one that can't recieve connections) works fine with LAN Ips, so the socket is free, and must be being blocked somewhere else

I have no idea what could be causing this

[Tonyf84]

I'm still a bit unclear about how this is set up. your game works fine over the internet...the app you wrote does not, but works fine over the lan....

I can think of a few things that would be the problem. first, your app isn't configured to use port 4050 as you think it is. Second, although you have port forwarding on, you may have a rule on the firewall to block that port.

The best way to figure out what's going on is to install wireshark (it's free) and do a packet capture while you try to connect to your app from the internet and again while connecting from the LAN. I suspect that when you look at the capture file from the internet connection attempt, you'll find that no packets matching that socket will appear. I also suspect that you'll see the LAN connection to that app coming in on a different port.

Try that first and see where it goes.

[Al42]

Where is which port being blocked (LAN or WLAN connection)?

What is the topography? WAN to router to WAP? Or WAN to WAP to router? Also what are the addresses of the router and the WAP? (If the problem is on the WLAN side, just turn off NAT in the WAP and connect one of its LAN ports to the router.)

If the WAP has a router, just configure it the same as your existing router and move the cables, eliminating the dual-NAT problem that you may be generating.

Check with http://www.portforward.com if you still can't figure it out or you don't get enough help here.