diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index 621eb39..f73faee 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -120,6 +120,7 @@
 
 	if (!(listener->rx.flags & RX_F_BOUND)) {
 		msg = "receiving socket not bound";
+		err |= ERR_FATAL | ERR_ALERT;
 		goto uxst_return;
 	}