diff --git a/auth.h b/auth.h
index c51717f..b39e48d 100644
--- a/auth.h
+++ b/auth.h
@@ -123,6 +123,7 @@
 #endif /* KRB5 */
 
 #include "auth-pam.h"
+void disable_forwarding(void);
 
 void	do_authentication(Authctxt *);
 void	do_authentication2(Authctxt *);