diff --git a/src/vnet/devices/tap/tapv2.api b/src/vnet/devices/tap/tapv2.api
index ccbbe15..9113458 100644
--- a/src/vnet/devices/tap/tapv2.api
+++ b/src/vnet/devices/tap/tapv2.api
@@ -30,6 +30,7 @@
         TAP_FLAG_CSUM_OFFLOAD = 2,
 	TAP_FLAG_PERSIST = 4,
 	TAP_FLAG_ATTACH = 8,
+	TAP_FLAG_TUN = 16,
 };
 
 /** \brief Initialize a new tap interface with the given parameters