diff --git a/src/vnet/interface_funcs.h b/src/vnet/interface_funcs.h
index 6f7ed11..1f22e80 100644
--- a/src/vnet/interface_funcs.h
+++ b/src/vnet/interface_funcs.h
@@ -274,7 +274,7 @@
 /* Change interface mac address*/
 clib_error_t *vnet_hw_interface_change_mac_address (vnet_main_t * vnm,
 						    u32 hw_if_index,
-						    u64 mac_address);
+						    u8 * mac_address);
 
 /* Change rx-mode */
 clib_error_t *set_hw_interface_change_rx_mode (vnet_main_t * vnm,