diff --git a/appl/telnet/libtelnet/auth-proto.h b/appl/telnet/libtelnet/auth-proto.h
index c49fff265..e462fb4a3 100644
--- a/appl/telnet/libtelnet/auth-proto.h
+++ b/appl/telnet/libtelnet/auth-proto.h
@@ -107,7 +107,7 @@ void kerberos4_is (Authenticator *, unsigned char *, int);
 void kerberos4_reply (Authenticator *, unsigned char *, int);
 int kerberos4_status (Authenticator *, char *, int);
 void kerberos4_printsub (unsigned char *, int, unsigned char *, int);
-int kerberos4_forward(Authenticator *ap, des_cblock *);
+int kerberos4_forward(Authenticator *ap, void *);
 #endif
 
 #ifdef	KRB5