diff --git a/net/tap-linux.c b/net/tap-linux.c
index 0f621a2315..e4f7e2723b 100644
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -52,6 +52,8 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required
             features & IFF_VNET_HDR) {
             *vnet_hdr = 1;
             ifr.ifr_flags |= IFF_VNET_HDR;
+        } else {
+            *vnet_hdr = 0;
         }
 
         if (vnet_hdr_required && !*vnet_hdr) {