diff --git a/metropolis/node/net_ips.go b/metropolis/node/net_ips.go
index 27bc4b1..415f84d 100644
--- a/metropolis/node/net_ips.go
+++ b/metropolis/node/net_ips.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package node
 
 import "net"