Solved. I've added some lines to vhost:
ServerName http:// purge.comain.com
ProxyPass / http:// varnish_server:9000/ ProxyPassReverse / http:// varnish_server:9000/
ErrorLog logs/purge. cloud-turner.com.ar-error_log CustomLog logs/purge. cloud-turner.com.ar-access_log combined
And added proxy.conf (/etc/httpd/conf.d/) with this line ProxyPreserveHost on
And that's it!