diff --git a/krebs/3modules/tinc_graphs.nix b/krebs/3modules/tinc_graphs.nix
index 486a0c9cc..33a24871f 100644
--- a/krebs/3modules/tinc_graphs.nix
+++ b/krebs/3modules/tinc_graphs.nix
@@ -37,6 +37,7 @@ let
 
       anonymous = mkOption {
         type = types.attrsOf types.unspecified;
+        default = {};
         description = ''
           nginx virtualHost options to be merged into the anonymous graphs
           vhost entry.