diff --git a/images/macvlan.proto b/images/macvlan.proto
index c9c90458e..0ca2652f0 100644
--- a/images/macvlan.proto
+++ b/images/macvlan.proto
@@ -1,3 +1,5 @@
+syntax = "proto2";
+
 message macvlan_link_entry {
 	required uint32	mode	= 1;
 	optional uint32 flags	= 2;