Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

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Aniket_G_182203's avatar
Aniket_G_182203
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Jan 20, 2015
Solved

Pool member has been marked down by a monitor

Hi I am new to F5..Trying to learn. During configuration I found following problem, "Pool member has been marked down by a monitor". What does it mean? problem in monitor profile?  
  • shaggy_121467's avatar
    shaggy_121467
    Jan 20, 2015

    it's not necessarily a problem with the F5 - this message indicates that the pool member is currently failing the assigned monitor. If the monitor assigned to the pool is, for example, a TCP monitor, then the F5 is unable to connect to the pool member on the pool member's associated TCP port.

     

shaggy's avatar
shaggy
Icon for Nimbostratus rankNimbostratus
Jan 20, 2015

it's not necessarily a problem with the F5 - this message indicates that the pool member is currently failing the assigned monitor. If the monitor assigned to the pool is, for example, a TCP monitor, then the F5 is unable to connect to the pool member on the pool member's associated TCP port.

 

shaggy's avatar
shaggy
Icon for Nimbostratus rankNimbostratus
Jan 21, 2015
it depends on the type of server/service that you are monitoring. if the pool member is hosting an HTTPS site to which the F5 is forwarding traffic, then it should be an HTTPS monitor. Check out: https://support.f5.com/kb/en-us/solutions/public/12000/500/sol12531.html https://support.f5.com/kb/en-us/solutions/public/2000/100/sol2167.html