diff --git a/print-rt6.c b/print-rt6.c
index fe0e8575..c2f86ff4 100644
--- a/print-rt6.c
+++ b/print-rt6.c
@@ -153,7 +153,7 @@ rt6_print(netdissect_options *ndo, const u_char *bp, const u_char *bp2 _U_)
 		}
 
 		if (len % 2 == 1) {
-			ND_PRINT(" (invalid length %u)", len);
+			ND_PRINT(" [length %u]", len);
 			goto invalid;
 		}
 		len >>= 1;