diff --git a/src/libstrongswan/eap/eap.h b/src/libstrongswan/eap/eap.h
index b11bcb69a..f836a462f 100644
--- a/src/libstrongswan/eap/eap.h
+++ b/src/libstrongswan/eap/eap.h
@@ -75,6 +75,8 @@ enum eap_type_t {
 	EAP_RADIUS = 256,
 	/** not a method, select method dynamically based on client selection */
 	EAP_DYNAMIC = 257,
+	/** make sure the enum is large enough to hold vendor-specific types */
+	EAP_UNASSIGNED = 0xffffffff,
 };
 
 /**