extern BOOL allow_mx_to_ip; /* Allow MX records to -> ip address */
extern BOOL allow_unqualified_recipient; /* As it says */
extern BOOL allow_unqualified_sender; /* Ditto */
+#ifdef EXPERIMENTAL_ARC
+struct arc_set *arc_received; /* highest ARC instance evaluation struct */
+extern int arc_received_instance; /* highest ARC instance number in headers */
+extern int arc_oldest_pass; /* lowest passing instance number in headers */
+extern const uschar *arc_state; /* verification state */
+#endif
extern BOOL allow_utf8_domains; /* For experimenting */
extern uschar *authenticated_fail_id; /* ID that failed authentication */
extern uschar *authenticated_id; /* ID that was authenticated */