Customize External monitor not working to achieve service based failover

[Rahul_Yadav]

Let me explain in detail.

We are running 3 different application on 2 IIS servers with different IPs on same port 80.

And F5 - LTM using LB to availability and LB part.

We have tried default http monitor but f5 unable to detect if we forcefully down the website from IIS server.

Second method we have tried with customize HTTP monitor, still unable to read the receive string.

Please suggest if someone have faced this issue in Past.

[MaryV]

What does your monitor configuration look like. Are there more than one monitors assigned to the pool is so have you by any chance specified availability requirement. Make sure your monitor complies to https://support.f5.com/csp/article/K2167, also what version are you running on? You may have to take under consideration a known issue described here https://support.f5.com/csp/article/K77256432.