I have roundube installed on one server that supports 2 servers. I put in the configuration file config ['default_host'] = 'ssl: //mail.'.'%s'; which causes the host mail to be set after @. Everything works fine, but it seems to me that my solution is not entirely secure because people from other servers will be able to log in and use my e-mail. Of course, I can set each person to choose a given server, but I would like it to work automatically. I change file index.php and now working and i can login accounts with two server but i don't know this solution is security? $auth = $RCMAIL->plugins->exec_hook('authenticate', array( 'host' => $RCMAIL->autoselect_host(), 'host2' => $RCMAIL->autoselect_host(), 'user' => trim(rcube_utils::get_input_value('_user', rcube_utils::INPUT_POST)), 'pass' => rcube_utils::get_input_value('_pass', rcube_utils::INPUT_POST, true, $pass_charset), 'valid' => $request_valid, 'cookiecheck' => true, )); $auth['host'] = 'ssl://mail.name.com'; $auth['host2'] = 'ssl://mail.name2.com'; // Login if ($auth['valid'] && !$auth['abort'] && $RCMAIL->login($auth['user'], $auth['pass'], $auth['host'], $auth['cookiecheck']) || $RCMAIL->login($auth['user'], $auth['pass'], $auth['host2'], $auth['cookiecheck']) )