diff --git a/tools/tunslip6.c b/tools/tunslip6.c
index 861868c84..b4390eacf 100644
--- a/tools/tunslip6.c
+++ b/tools/tunslip6.c
@@ -238,13 +238,21 @@ serial_to_tun(FILE *inslip, int outfd)
 	  slip_send(slipfd, SLIP_END);
         }
 #define DEBUG_LINE_MARKER '\r'
-      } else if(uip.inbuf[0] == DEBUG_LINE_MARKER) {
-	fwrite(uip.inbuf + 1, inbufptr - 1, 1, stdout);
-      } else if(is_sensible_string(uip.inbuf, inbufptr)) {
-        if(verbose==1) {   /* strings already echoed below for verbose>1 */
-          if (timestamp) stamptime();
-          fwrite(uip.inbuf, inbufptr, 1, stdout);
-        }
+	if(uip.inbuf[0] == DEBUG_LINE_MARKER ||
+           is_sensible_string(uip.inbuf, inbufptr)) {
+          unsigned char *out = uip.inbuf;
+          unsigned int   len = inbufptr;
+          if(uip.inbuf[0] == DEBUG_LINE_MARKER) {
+            out++;
+            len--;
+          }
+          fprintf(stderr, "\n***");
+	  fwrite(out, len, 1, stderr);
+          fprintf(stderr, "***\n");
+	} else {
+	  fprintf(stderr,
+		  "serial_to_tun: drop packet len=%d\n", inbufptr);
+	}
       } else {
         if(verbose>2) {
           if (timestamp) stamptime();