Fiddler shows -Virtual Server actively refused connection

Could you please give more information;

deployment mode, gateway of IIS, snat etc.

I'm currently not in a position to reproduce this issue, but I thought I might give you a hint.

Do you have Auto Map option selected on Source Address Translation setup of the virtual server? If you don't, try turning this option on. If you do have this option enabled try performing a request to your pool members from the BIG-IP device using curl.

Let me know if this helps.

This could be network configuration issue or SNAT. I think you need to sort out the monitoring issue first before troubleshooting further. Try to use ICMP monitor and see if it works. If ICMP monitor works, check using TCP monitor. If TCP monitor fails but ICMP monitor had worked previously, this could indicate route asymmetry issues.

If possible try to sketch out packet flow from client to F5 to server and back based on existing network configuration in order to identify any issues.

Hi,

if the monitors are not working then first that should be resolved, this may lead to resolving the other issue. What monitors have your configured? is there a firewall between F5 and IIS server? if yes, are you allowing monitor traffic on the firewall?