Linux – nginx load balance with IIS backend servers waiting Host header

Turns out nginx has quite a lot of proxy redirect options to deal with this sort of problems. I ended up using something like this:

location / {
    proxy_pass  http://myproject;
    proxy_set_header Host myproject;
    proxy_redirect http://myproject/ $scheme://$host/;
    proxy_redirect http://myproject:8000/ $scheme://$host/;
}

This basically replaces the upstream name with the $host and removes the port. This worked in my case because I am hosting nginx on the default ports for HTTP/HTTPS. If nginx is running on a non-default port, something like this is needed:

    proxy_redirect http://myproject/ $scheme://$host:$server_port/;
    proxy_redirect http://myproject:8000/ $scheme://$host:$server_port/;

I believe you need a separate server block for HTTP. For example:

server {
listen 80;

location / {
        proxy_redirect off;
        proxy_cache off;
        proxy_pass         http://127.0.0.1:5000;
        proxy_set_header   Host             $http_host;
        proxy_set_header   X-Real-IP        $remote_addr;
        proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
}
}

You would then remove listen 80; from the existing server block.