diff --git a/configuration.nix b/configuration.nix
index b3962ef..bcc3d0e 100644
--- a/configuration.nix
+++ b/configuration.nix
@@ -338,7 +338,10 @@
       extraConfig = disableLog + enableSTS;
 
       # Returns IP address
-      locations."/ip".extraConfig = "return 200 $remote_addr;";
+      locations."/ip".extraConfig = ''
+        default_type text/plain;
+        return 200 $remote_addr;
+      '';
 
       # Asjon code coverage reports
       locations."/asjon/report/" = {