Avoid Deprecation warning
PHP Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /usr/local/ispconfig/server/plugins-available/bind_plugin.inc.php on line 397
PHP Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /usr/local/ispconfig/server/plugins-available/bind_plugin.inc.php on line 397