Pass through X-Forwarded-Host if set

Author: itskingori

config/http.conf

@@ -21,6 +21,13 @@ http {
   port_in_redirect          off;
   server_tokens             off;
 
+  # If we receive X-Forwarded-Host, pass it through; otherwise, pass along the
+  # host used to connect to this server
+  map $http_x_forwarded_host $proxy_x_forwarded_host {
+    default $http_x_forwarded_host;
+    ''      $host;
+  }
+
   # If we receive X-Forwarded-Proto, pass it through; otherwise, pass along the
   # scheme used to connect to this server
   map $http_x_forwarded_proto $proxy_x_forwarded_proto {
@@ -69,7 +76,7 @@ http {
   proxy_set_header    X-Forwarded-Ssl     $proxy_x_forwarded_ssl;
   proxy_set_header    X-Forwarded-Port    $proxy_x_forwarded_port;
   proxy_set_header    X-Request-ID        $proxy_x_request_id;
-  proxy_set_header    X-Forwarded-Host    $host;
+  proxy_set_header    X-Forwarded-Host    $proxy_x_forwarded_host;
 
   include /etc/nginx/app.conf;