allow custom host header for azure load balancer health probes
HTTP health probes for Azure load balancer are hard-coded to use the IP of backend as their host headers. This forces the backend hosts have to be configured to allow its IP as one of its allowed domain. It's very surprising that Azure doesn't custom host header for HTTP(s) health probes. Please add custom headers for HTTP(s) heath probes; at least, host header support should be there.
Thank you for the feedback. Need to investigate what is possible.
Jeff Little commented
As the requester said, the HTTP healthprobes require you to have an IIS binding of *:443.
This prevents you from having other IIS sites running on the same IP with different probes as only 1 binding of *:443 can be put on an IP.
The workaround is probably to add/manage an IP for each IIS instance, but that defeats the point of virtual hosts.