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rodmarso's avatar
rodmarso
Icon for Nimbostratus rankNimbostratus
Feb 16, 2026
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F5 Local traffic Pool -> How does it track the availability of the members of the pool?

Hi Team,

 

I would like to understand how the Pool works on F5, please.

 

In terms of F5 Local Traffic Pool, how does it track the availability (green/red) of the members of it?

 

I mean, does it use the F5 management IP as a source for this tracking ?

Is there a way we can configure the source to be a specific Self IP? If yes, how is that done?

 

Thank you

Rodrigo

  • The F5 uses the IP closest to the destination as the IP for health monitoring. So if you had 3 interface excluding management, external, dmz, and internal and your destination IP for a pool member existed in a subnet routed out the external interface you would see the health monitor come from the external interface, this is regardless of which subnet the virtual server exists in that the pool in question is configured under. You could theoretically have pool members in those 3 segments and balance traffic to them but that would cause a whole other issue with needing to configure SNAT but that's a different question. Even in an HA configuration the health monitor comes from the self-ip of the closest interface. I'm not aware of any way to force health monitors to come from a specific IP other than having that IP be the interface IP of the F5 in question.

3 Replies

  • The F5 uses the IP closest to the destination as the IP for health monitoring. So if you had 3 interface excluding management, external, dmz, and internal and your destination IP for a pool member existed in a subnet routed out the external interface you would see the health monitor come from the external interface, this is regardless of which subnet the virtual server exists in that the pool in question is configured under. You could theoretically have pool members in those 3 segments and balance traffic to them but that would cause a whole other issue with needing to configure SNAT but that's a different question. Even in an HA configuration the health monitor comes from the self-ip of the closest interface. I'm not aware of any way to force health monitors to come from a specific IP other than having that IP be the interface IP of the F5 in question.

  • Thank you Paulius. That was I suspected.  We can close this one. Thanks again.

    • Melissa_C's avatar
      Melissa_C
      Icon for Moderator rankModerator

      Hello rodmarso​ 

      If the response Paulius provided helped with answering your questions, I would like to encourage you to Mark as Solution. This will allow for others who may have these questions in the future find the answer. 

      Thank you for posting to our community. 

      -Melissa