Windows 2k8 Firewall Response For Not Opened Port Is Slow RRS feed

  • Question

  • Hi, 

    I am using Telnet (have also tried with PortQuery) to see if some specific port is listening or not, but the response is very slow, about 20 seconds.

    Note that I have set this port to allow the traffic in the firewall inbounding rules.

    However, on the earlier versions of Windows Firewall (XP, 2003) the response is very fast, about 1-2 seconds.

    How can I configure Windows 2008 Firewall in order to get faster response?

    Thank you


    Friday, July 23, 2010 10:21 AM

All replies

  • Hi,

    have you deployed any AV or other firewall software?

    what if you disable firewall?

    and try to using network monitor to capture traffic when you perform telnet .

    two links for you reference 





    Friday, July 23, 2010 12:49 PM
  • Hi liyin,

    Disabling TCP chimney and rss features does not help.

    But when firewall is disabled the response is immediately, 1-2 sec.

    I have tried some other settings found on internet, but nothing works. 

    Please that Telnet is used just for testing tool of the port open test, the same happens using other tools or for example java sockets.



    Friday, July 23, 2010 1:31 PM
  • Hi,

    Thanks for the post.

    Based on my test, it may take 20 seconds to get a response from a blocked port.

    From your description, you said that you have set the port to allow the traffics in the firewall inbounding rules but it still gets the slow response; however, the title of this post is "Windows 2k8 Firewall Response For Not Opened Port Is Slow". I am a little confused about it. Would you please confirm with me?

    Meanwhile, I am wondering if this problem is involved with the other ports?





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    Monday, July 26, 2010 10:22 AM
  • Hi,

    Thanks for reply.


    I will describe the problem once again:

    1. The port is allowed by the firewall rule, but is not opened (i.e. there is no application that opens this port on server)

    2. Using telnet command: telnet <ip> <port>: the response that this port is not opened is about 20 seconds.


    But, with the same settings on Windows 2003 Server with its Firewall enabled, result is different, response returns within 1-2 seconds.

    So, it is obvious that 2008 Firewall is doing some additional checks, but I do not know what exactly and how I can disable it.


     Any question or suggestion is very welcome.








    Monday, July 26, 2010 12:42 PM
  • No replies? 

    Wednesday, July 28, 2010 11:14 AM