Change cache server host in FrontEnd cache

Hi all

I read help about cache in Xenforo here:

In frontend, I want to change server cache to another server (not localhost - default - I think that). But I don't see option (host, servers, etc...) to do that

Here is current configuration:
$config['cache']['enabled'] = true;
$config['cache']['frontend'] = 'Core';
$config['cache']['frontendOptions'] = array (
'caching' => true ,
'automatic_serialization' => true ,
'Lifetime' => 1800,
'cache_id_prefix' => 'xf_'

$config['cache']['backend'] = 'Libmemcached';

So can you help me :(