diff --git a/include/ntapi/nt_socket.h b/include/ntapi/nt_socket.h
index aceb781..f696f68 100644
--- a/include/ntapi/nt_socket.h
+++ b/include/ntapi/nt_socket.h
@@ -140,6 +140,12 @@
 
 
 
+/* afd socket option levels */
+#define NT_SOL_IPV6				41
+#define NT_SOL_SOCKET				0xffff
+
+
+
 /* afd ipv6 socket options */
 #define NT_IPV6_HOPOPTS				1
 #define NT_IPV6_HDRINCL				2