diff --git a/src/rtty.c b/src/rtty.c
index ac9ed65..23be4c3 100644
--- a/src/rtty.c
+++ b/src/rtty.c
@@ -313,6 +313,11 @@ static int parse_msg(struct rtty *rtty)
             return 0;
 
         msgtype = buffer_pull_u8(rb);
+        if (msgtype > MSG_TYPE_MAX) {
+            log_err("invalid message type: %d\n", msgtype);
+            return -1;
+        }
+
         buffer_pull_u16(rb);
 
         switch (msgtype) {
@@ -360,8 +365,7 @@ static int parse_msg(struct rtty *rtty)
             break;
 
         default:
-            log_err("invalid message type: %d\n", msgtype);
-            buffer_pull(rb, NULL, msglen);
+            /* never to here */
             break;
         }
     }
diff --git a/src/rtty.h b/src/rtty.h
index ca4587f..529924e 100644
--- a/src/rtty.h
+++ b/src/rtty.h
@@ -41,15 +41,16 @@
 #define RTTY_HEARTBEAT_INTEVAL      5.0
 
 enum {
-    MSG_TYPE_REGISTER = 0x00,
-    MSG_TYPE_LOGIN = 0x01,
-    MSG_TYPE_LOGOUT = 0x02,
-    MSG_TYPE_TERMDATA = 0x03,
-    MSG_TYPE_WINSIZE = 0x04,
-    MSG_TYPE_CMD = 0x05,
-    MSG_TYPE_HEARTBEAT = 0x06,
-    MSG_TYPE_FILE = 0x07,
-    MSG_TYPE_WEB = 0x08
+    MSG_TYPE_REGISTER,
+    MSG_TYPE_LOGIN,
+    MSG_TYPE_LOGOUT,
+    MSG_TYPE_TERMDATA,
+    MSG_TYPE_WINSIZE,
+    MSG_TYPE_CMD,
+    MSG_TYPE_HEARTBEAT,
+    MSG_TYPE_FILE,
+    MSG_TYPE_WEB,
+    MSG_TYPE_MAX = MSG_TYPE_WEB
 };
 
 struct rtty;