diff --git a/epan/dissectors/packet-tacacs.c b/epan/dissectors/packet-tacacs.c
index 25e6fcfb85..ba932bfe3c 100644
--- a/epan/dissectors/packet-tacacs.c
+++ b/epan/dissectors/packet-tacacs.c
@@ -58,6 +58,10 @@
 #include <winsock2.h>		/* needed to define AF_ values on Windows */
 #endif
 
+#ifdef NEED_INET_V6DEFS_H
+# include "inet_v6defs.h"
+#endif
+
 #include <glib.h>
 #include <epan/packet.h>