I have set up several servers with IIS and connected them to the load balancer - server with installed IIS Application Request Routing. I have created a server farm and added two servers. Then I stopped IIS on the first server and tried to open my web site. It returned me an error:
502 - Web server received an invalid response while acting as a gateway or proxy server.
[There is a problem with the page you are looking for, and it cannot be displayed. When the Web server (while acting as a gateway or proxy) contacted the upstream content server, it received an invalid response from the content server.]
But if instead of stopping IIS I shut down the first server, I'm getting a response from the next server which is online. The question is, what the expected behaviour should be for failover with ARR, should it switch me to the next server if IIS is stopped and server is online?
Additional info: I've tried to shut down each server and I was able to open web site in both cases, so there is no problem with connections or configuration. I'm using even distribution and round-robin load balance algorithm. The problem appears only if I stop IIS and leave server online.