diff --git a/src/detect-parse.c b/src/detect-parse.c
index ebfd4d7f3241..d9b5c772ac71 100644
--- a/src/detect-parse.c
+++ b/src/detect-parse.c
@@ -1324,7 +1324,11 @@ static int SigParseProto(Signature *s, const char *protostr)
         char *xsaveptr = NULL;
         p = strtok_r(proto, ":", &xsaveptr);
         h = strtok_r(NULL, ":", &xsaveptr);
-        SCLogNotice("p: '%s' h: '%s'", p, h);
+        SCLogDebug("p: '%s' h: '%s'", p, h);
+    }
+    if (p == NULL) {
+        SCLogError("invalid protocol specification '%s'", proto);
+        return -1;
     }
 
     int r = DetectProtoParse(&s->proto, p);