diff --git a/test/tests.nix b/test/tests.nix
index 9c7773b..1d74b40 100644
--- a/test/tests.nix
+++ b/test/tests.nix
@@ -51,6 +51,7 @@ let
       tests.clightning = cfg.clightning.enable;
       test.data.clightning-replication = cfg.clightning.replication.enable;
 
+      # TODO-EXTERNAL:
       # When WAN is disabled, DNS bootstrapping slows down service startup by ~15 s.
       services.clightning.extraConfig = mkIf config.test.noConnections "disable-dns";
       test.data.clightning-plugins = let