diff --git a/javascript/udp/detection/tftp-detect.yaml b/javascript/udp/detection/tftp-detect.yaml
index 0c48085b27..8849374ba3 100644
--- a/javascript/udp/detection/tftp-detect.yaml
+++ b/javascript/udp/detection/tftp-detect.yaml
@@ -12,7 +12,9 @@ info:
     shodan-query: "port:69"
   tags: js,tftp,udp,network
 javascript:
-  - code: |
+  - pre-condition: |
+      isUDPPortOpen(Host,Port);
+    code: |
       let packet = bytes.NewBuffer();
       let message = "1.txt"
       let data = message;
@@ -32,4 +34,3 @@ javascript:
         words:
           - "Unknown transfer ID"
         case-insensitive: true
-# digest: 4a0a00473045022100c512c1a23c479681469c4b6a1e1e7a5740dfee043f58cb2a1d79767822cbb32802203dfa42884afa515fb2ac6dd0e0075422bc1f3ece618c6538164c8b9b09062e46:922c64590222798bb761d5b6d8e72950