LTM Health Monitors

HI, its actually quite simple, if you have web server, which hosts only one web application and listent to all incoming web requests (not checking HTTP 'Host' header), then of course it'll be successful. For example, when you're first starting new web server on IIS or Apache, they both have default landing page with platform information. So your year health monitor will definitely work for that page.

I suggest you to turn on Health monitor logging and then check logs in /var/log/monitors/ directory. Also you can test your health monitor via curl utility. You can test it directly with your web server, without f5 and will see that the very same request string will be successful.

So, in short, you should check the configuration on your web server's side, if it's apache, you can look at this url:

https://httpd.apache.org/docs/trunk/vhosts/name-based.html