diff --git a/bgpd/bgp_open.h b/bgpd/bgp_open.h
index 014bc33..aa7f8cb 100644
--- a/bgpd/bgp_open.h
+++ b/bgpd/bgp_open.h
@@ -18,6 +18,9 @@
 Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 02111-1307, USA.  */
 
+#ifndef _QUAGGA_BGP_OPEN_H
+#define _QUAGGA_BGP_OPEN_H
+
 /* MP Capability information. */
 struct capability_mp
 {
@@ -79,3 +82,5 @@
 int bgp_open_option_parse (struct peer *, u_char, int *);
 void bgp_open_capability (struct stream *, struct peer *);
 void bgp_capability_vty_out (struct vty *, struct peer *);
+
+#endif /* _QUAGGA_BGP_OPEN_H */