check_host
{ "http_proxy", krb5_config_string, check_host /* XXX */ },
{ "kdc", krb5_config_string, check_host },
{ "admin_server", krb5_config_string, check_host },
{ "kpasswd_server", krb5_config_string, check_host },
{ "krb524_server", krb5_config_string, check_host },