diff --git a/src/index.js b/src/index.js
index e0904d5..8b0e873 100644
--- a/src/index.js
+++ b/src/index.js
@@ -7,7 +7,7 @@ const multiaddr = require('multiaddr')
  */
 const DNS4 = base('dns4')
 const DNS6 = base('dns6')
-const DNS = or(
+const _DNS = or(
   base('dns'),
   DNS4,
   DNS6
@@ -18,6 +18,11 @@ const TCP = and(IP, base('tcp'))
 const UDP = and(IP, base('udp'))
 const UTP = and(UDP, base('utp'))
 
+const DNS = or(
+  and(_DNS, base('tcp')),
+  _DNS
+)
+
 const WebSockets = or(
   and(TCP, base('ws')),
   and(DNS, base('ws'))
diff --git a/test/index.spec.js b/test/index.spec.js
index 3c61058..b1f73ea 100644
--- a/test/index.spec.js
+++ b/test/index.spec.js
@@ -10,7 +10,10 @@ describe('multiaddr validation', function () {
     '/dns/ipfs.io',
     '/dns4/ipfs.io',
     '/dns4/libp2p.io',
-    '/dns6/protocol.ai'
+    '/dns6/protocol.ai',
+    '/dns4/protocol.ai/tcp/80',
+    '/dns6/protocol.ai/tcp/80',
+    '/dns/protocol.ai/tcp/80'
   ]
 
   const badDNS = [