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Srinivasan_G_31's avatar
Srinivasan_G_31
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Dec 01, 2014

Http Health monitor

Friends - i have an issue with a http pool where the standard/default http health monitor that comes with the system (GET /\r\n in the Get string and a blank space in the receive) doesn't seem to be working. When i do away with the Get string and perform a simple probe on port 80 (either tcp or http), it is working. Any suggestions?

 

4 Replies

  • The default does a HTTP 0.9 request that some web servers don't respond to. What you may want is something like:

    GET / HTTP/1.1\r\nHost: example.com\r\nConnection: Close\r\n\r\n

    One other thing to keep in mind is that a web server with multiple virtual hosts on the same IP needs a distinctive

    Host
    header, so you may need to change the example.com above to the name of your website.

  • THi's avatar
    THi
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    I suggest to use a specific receive string. If the receive string is left blank, it will accept any response the server sends back, including error pages (like 4xx/5xx server errors) as valid responses, and will mark the server up. Typically only timeout marks the server down with empty receive string.

     

    You can use some info string from the header part of the response, like 200 OK, or any unique text string from the beginning of the normal response page. Use fiddler, firebug or similar tool to check what a valid response page sends (including headers).

     

    The default http monitor buffer size is 5120 bytes, so the receive string needs to appear within that, especially before any images on the rendered response page.