Index: mcs/class/System/System.Net.NetworkInformation/OpenBSDNetworkInterface.cs
--- mcs/class/System/System.Net.NetworkInformation/OpenBSDNetworkInterface.cs.orig
+++ mcs/class/System/System.Net.NetworkInformation/OpenBSDNetworkInterface.cs
@@ -0,0 +1,37 @@
+//
+// System.Net.NetworkInformation.NetworkInterface
+//
+// Authors:
+//	Robert Nagy (robert@openbsd.org)
+//	Conrad Meyer (cem@FreeBSD.org)
+//
+// Copyright (c) 2020, 2019 Conrad Meyer, Robert Nagy
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+namespace System.Net.NetworkInformation {
+	internal class OpenBSDNetworkInterfaceAPI : MacOsNetworkInterfaceAPI
+	{
+		public OpenBSDNetworkInterfaceAPI ()
+			: base (AF_INET6: 24)
+		{
+		}
+	}
+}
