--- a/mod_firewall/definitions.lib.lua	Wed Feb 22 22:47:45 2023 -0500
+++ b/mod_firewall/definitions.lib.lua	Sat May 06 19:40:23 2023 -0500
@@ -197,7 +197,11 @@
 	-- TODO Invent some custom schema for this? Needed for just a set of strings?
 	pubsubitemid = {
 		init = function(self, pubsub_spec, opts)
-			local service_addr, node = pubsub_spec:match("^([^/]*)/(.*)");
+			local service_addr, node = pubsub_spec:match("^pubsubitemid:([^/]*)/(.*)");
+			if not service_addr then
+				module:log("warn", "Invalid list specification (expected 'pubsubitemid:<service>/<node>', got: '%s')", pubsub_spec);
+				return;
+			end
 			module:depends("pubsub_subscription");
 			module:add_item("pubsub-subscription", {
 					service = service_addr;