diff --git a/lib/utils/ip.js b/lib/utils/ip.js
index 718fe767..36ca499a 100644
--- a/lib/utils/ip.js
+++ b/lib/utils/ip.js
@@ -199,7 +199,7 @@ IP.isMapped = function isMapped(buf) {
   assert(Buffer.isBuffer(buf));
   assert(buf.length === 16);
 
-  if (buf[10] !== 0xff && buf[11] !== 0xff)
+  if (buf[10] !== 0xff || buf[11] !== 0xff)
     return false;
 
   for (i = 0; i < 10; i++) {