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Adam_Miceli_144's avatar
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Jan 08, 2012

https_443 health monitor incorrectly detects node down

Hi All, I have the F5 LTM load-balancing 2 Exchange 2010 servers. Recenlty, it dropped one of the nodes out of the pool because the https_443 health monitor is detecting that the node is down. However, the node is not down. I can telnet to TCP 443, and access OWA using a server-specific URL. Any idea what could be causing the false positive?



Thanks, Adam



4 Replies

  • Michael_Shimku2's avatar
    Historic F5 Account
    Hi Adam, assuming the monitor send and receive strings have not changed, I would take a packet capture between the BIG-IP and the Exchange server. If you have access to the SSL certificate used on the server, you can use Wireshark to decrypt the monitor traffic and find out what response the server is sending that is causing the monitor to fail.
  • Ryan_Korock_46's avatar
    Historic F5 Account
    Adam, do you mind also posting the monitor configuration?



    You can pull a text version of the BIG-IP configuration by going to System -> Support and creating a QKView. Inside the QKView you can find the monitor configuration.



    Michael is right, and that a capture would be definitive, however we might be able to discover the issue with how the monitor is configured as well.
  • Hi Guys, thanks for the responses. What I did yesterday to resolve the problem is examined the IIS configs on my two Exchange servers, and noticed that the root of the Default Web Site was requiring SSL. I did not think that was correct, so I unchecked it and ran IISRESET. That seemed to resolve the issue. It seems odd that both Exchange servers were configured this way, yet only one was getting a false positive from the monitor.



    Ryan, when I go to System > Support, the only option I have is "Download Snapshot File". Is that what you are referring to?



  • Helen_Johnson_1's avatar
    Historic F5 Account
    Hi Adam,



    Glad to hear your issue was resolved.



    To answer your question, we use the terms snapshot and qkview interchangeably. You should have the ability to put a check box next to qkview and hit the start button below your checkable options. Then you'll be able to download the completed file.



    For next time... :)