diff --git a/configure.in b/configure.in
index 148ac9553..1269e6a2a 100644
--- a/configure.in
+++ b/configure.in
@@ -96,6 +96,13 @@ if test "$enable_kx509" != no ;then
 	AC_DEFINE([KX509], 1, [Define to enable kx509.])
 fi
 
+AC_ARG_ENABLE(krb4, 
+	AS_HELP_STRING([--disable-krb4],
+		[if you want disable to krb4 support]))
+if test "$enable_krb4" != no ;then
+	AC_DEFINE([KRB4], 1, [Define to enable Kerberos 4.])
+fi
+
 
 dnl Check for sqlite
 rk_TEST_PACKAGE(sqlite3,