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v2's avatar
Icon for Nimbostratus rankNimbostratus
Jan 31, 2023

Send commands to internal servers and examine the response


i have a requirement where we need the Big-IP device to send a command to servers in a pool and then analyze the response to determine the health of an application on the pool members.  Is this possible, and how can it be implemented?




4 Replies

  • v2 depending on the type of connection you have to the pool members such as HTTP, HTTPS, RDP, and others, you should be able to use the send string to send a specific command and the receive string to search for a specific response back. The send and receive string are configureable in the health monitor for certain health monitor types but please keep in mind that I believe after 256 lines or possibly a specific data size the F5 will stop process the response so if the text exists beyond that cutoff it will fail the health monitor. If you can provide an example of what you need to test we might be able to come up with the appropriate health monitor to meet your needs.

    • v2's avatar
      Icon for Nimbostratus rankNimbostratus

      hello Paulius 

      We need to send a message using SSH to the pool members and then examine the response. the send string and receive strings are as below

      Request raw message 00670800822000000800000004000000000000000201113130627730303211627730003
      Request breakdown (MTI)(0800),(7)(0201113130),(11)(627730),(37)(303211627730),(70)(003),


      Response raw message 00701814822000000A00000004000000000000000201113130627730303211627730000003
      Response breakdown (MTI)(0810),(7)(0201113130),(11)(627730),(37)(303211627730),(39)(00),(70)(003)


  • Hi v2  - did the article Paulius linked help you?

    Also, I have to ask - is your username named after a version, the first rocket to reach space, or for something else?