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  • Question

  • Win7, Win 2008, WIn 08 R2

    I have an inhouse program that needs to be able to communicate using TCP port 50,000. Even if I add a firewall port rule or even if I turn the firewall off I'm not able to connect. When I do a port scan I see that no matter what I do its blocked. Any ideas?


    • Edited by jamicon Wednesday, September 28, 2011 12:58 PM
    Wednesday, September 28, 2011 12:13 PM

Answers

  • For starters, you can use TCPView utility (http://technet.microsoft.com/en-us/sysinternals/bb897437) that'll show you a detailed description of the network connections. Install it on the server and the client, analyze it to isolate where the problem lies.

    The overall implementation should be like this:

    • Create an Allow Inbound rule on port 50000 of the client firewall (since client is listening)
    • Create an Allow Outbound rule on port 50000 of the server firewall (since server is sending)

    If the firewall is off, Windows will not block any incoming packets, unless there is a 3rd party firewall blocking it. Are you sure that the port number on the client and the server are the same? It sometimes may be possible that the local computer may be using a port number different from the remote computer.

    Please revert back here if the above information does not help you resolve the issue. Hope it helps!


    Kunal D Mehta - a Windows Server Enthusiast | I'm on facebook.com/serverbaba
    • Marked as answer by jamicon Thursday, September 29, 2011 3:04 PM
    Thursday, September 29, 2011 2:50 PM

All replies

  • First thoughts is that your application is trying to use other ports to send on.  You should look at using something to capture network packets as you run the application like Wireshark.
    :P Advice offered, If you need more help it is advised to seek the council and advice of paid professionals. The answer is always 42, or reboot.
    Thursday, September 29, 2011 12:29 AM
  • yes that would help, more than netstat -an however we know the client is listening on port 50000 and the server is sending on port 50000 and even with the firewall off it times out. We have double checked this. I guess I just need to know for sure that if the firewall is off that the OS is not blocking any income packets, would that be safe to assume with win7?
    Thursday, September 29, 2011 1:51 PM
  • You can tell is your firewall is enabled or not through the control panel,  I would double check with the dev guys also, I have dealt with in house app development where they swear it only uses port so and so... only to find out they are making generic rpc calls, see if the app has a config that specifies port 50000
    :P Advice offered, If you need more help it is advised to seek the council and advice of paid professionals. The answer is always 42, or reboot.
    Thursday, September 29, 2011 2:12 PM
  • For starters, you can use TCPView utility (http://technet.microsoft.com/en-us/sysinternals/bb897437) that'll show you a detailed description of the network connections. Install it on the server and the client, analyze it to isolate where the problem lies.

    The overall implementation should be like this:

    • Create an Allow Inbound rule on port 50000 of the client firewall (since client is listening)
    • Create an Allow Outbound rule on port 50000 of the server firewall (since server is sending)

    If the firewall is off, Windows will not block any incoming packets, unless there is a 3rd party firewall blocking it. Are you sure that the port number on the client and the server are the same? It sometimes may be possible that the local computer may be using a port number different from the remote computer.

    Please revert back here if the above information does not help you resolve the issue. Hope it helps!


    Kunal D Mehta - a Windows Server Enthusiast | I'm on facebook.com/serverbaba
    • Marked as answer by jamicon Thursday, September 29, 2011 3:04 PM
    Thursday, September 29, 2011 2:50 PM