diff --git a/src/modules/trace/controller/tcpdump.go b/src/modules/trace/controller/tcpdump.go
index bb7f4449..62dc4f62 100644
--- a/src/modules/trace/controller/tcpdump.go
+++ b/src/modules/trace/controller/tcpdump.go
@@ -243,6 +243,14 @@ func (s *TcpdumpController) NeUPFTask(c *gin.Context) {
 			c.JSON(200, result.ErrMsg(err.Error()))
 			return
 		}
+		if strings.Contains(msg, "command not found") {
+			c.JSON(200, result.ErrMsg("Command [expect] Not Found"))
+			return
+		}
+		if strings.Contains(msg, "Unable to connect to remote host") {
+			c.JSON(200, result.ErrMsg("Connection Refused"))
+			return
+		}
 		s := strings.Index(msg, "pcap dispatch trace:")
 		if s == -1 {
 			s = strings.Index(msg, "Write ")