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nick_greenfield's avatar
nick_greenfield
Icon for Altostratus rankAltostratus
Jun 18, 2019

HTTP Health Monitor Failing, Not Sure Why

I tried creating a custom http health monitor for one of our applications with a simple SEND and RECIEVE configuration.   Send String: GET /application/URI/resource.ascx \r\n Receive String: HT...
  • jaikumar_f5's avatar
    jaikumar_f5
    Jun 18, 2019

    Can you make a simple change and let us know if it fixes,

     

    Send String: GET /application/URI/resource.ascx HTTP/1.1\r\nHost: www.domain.com\r\nConnection: Close\r\n\r\n

    Receive String: "200 OK"

     

iaine's avatar
iaine
Icon for Nacreous rankNacreous
Jun 18, 2019

Hi

 

You're not sending your request string as a HTTP/1.1 formatted string but you're receive string is looking for a 1.1 response - there' a great KB article on this - https://support.f5.com/csp/article/K2167 - that goes into great detail on http monitors with good examples.

 

Also, you can enable logging on your monitor to understand what is happening, see https://support.f5.com/csp/article/K12531 for more info on how to do this

  • Hamish's avatar
    Hamish
    Icon for Cirrocumulus rankCirrocumulus
    Jun 18, 2019

    Generally that won't be an issue. Except for the HTTP/0.9 request... (i.e. A lot of servers will reply 1.1 if you ask them a 1.0 request - even if it is technically out of spec)

    Change your request to at least HTTP/1.0 i.e.

    GET /application/URI/resource HTTP/1.0\r\n\r\n

    And make sure your server really does reply with HTTP/1.1 and not HTTP/1.0. if you do require an HTTP{/1.1 request you (should) have to add a few headers to make a real request. HTTP/1.1 made several of them 'mandatory'

    But like iaine said. Enable debug to see what is being compared. It's likely something small and 'obvious' once you've identified it