diff --git a/scripts/dns-srv-enum.nse b/scripts/dns-srv-enum.nse
index 1c6f081e1..d213a81b0 100644
--- a/scripts/dns-srv-enum.nse
+++ b/scripts/dns-srv-enum.nse
@@ -58,11 +58,11 @@ require 'dns'
 require 'tab'
 require 'target'
 
-prerule = function() return true end
-
 local arg_domain = stdnse.get_script_args(SCRIPT_NAME .. ".domain")
 local arg_filter = stdnse.get_script_args(SCRIPT_NAME .. ".filter")
 
+prerule = function() return not(not(arg_domain)) end
+
 local function parseSvcList(services)
 	local i = 1
 	return function()