While the mail error file is correctly black, it would be nice to include a statement for the user to see that no errors have been found.

I have a corrected the file to allow this to happen.

File: /usr/local/ispconfig/server/lib/classes/monitor_tools.inc.php

Original:

public function monitorMailErrLog() { global $conf;

            /* the id of the server as int */
            $server_id = intval($conf['server_id']);

            /** The type of the data */
            $type = 'log_mail_err';

            /* Get the data of the log */
            $data = 'No mail errors found.';

            /*
             * actually this info has no state.
             * maybe someone knows better...???...
             */
            $state = 'no_state';

            /*
             * Return the Result
             */
            $res['server_id'] = $server_id;
            $res['type'] = $type;
            $res['data'] = $data;
            $res['state'] = $state;
            return $res;
    }

Corrected:

public function monitorMailErrLog() { global $conf;

            /* the id of the server as int */
            $server_id = intval($conf['server_id']);

            /** The type of the data */
            $type = 'log_mail_err';

            /* Get the data of the log */
            if ( $this->_getLogData($type) == ''){
                    $data = 'No mail errors found.';
            } else {
                    $data = $this->_getLogData($type);
            };

            /*
             * actually this info has no state.
             * maybe someone knows better...???...
             */
            $state = 'no_state';

            /*
             * Return the Result
             */
            $res['server_id'] = $server_id;
            $res['type'] = $type;
            $res['data'] = $data;
            $res['state'] = $state;
            return $res;
    }

I know this seems like a trivial fix, but I do think that it is an improvement over the current blank or empty file.

Thanks.