diff --git a/programs/ssl/dtls_client.c b/programs/ssl/dtls_client.c
index acaae59..d8353a9 100644
--- a/programs/ssl/dtls_client.c
+++ b/programs/ssl/dtls_client.c
@@ -241,13 +241,17 @@
      * MBEDTLS_SSL_VERIFY_OPTIONAL, we would bail out here if ret != 0 */
     if( ( flags = mbedtls_ssl_get_verify_result( &ssl ) ) != 0 )
     {
+#if defined(MBEDTLS_X509_INFO)
         char vrfy_buf[512];
+#endif
 
         mbedtls_printf( " failed\n" );
 
+#if defined(MBEDTLS_X509_INFO)
         mbedtls_x509_crt_verify_info( vrfy_buf, sizeof( vrfy_buf ), "  ! ", flags );
 
         mbedtls_printf( "%s\n", vrfy_buf );
+#endif
     }
     else
         mbedtls_printf( " ok\n" );