<header>Regular expressions for disallowed domains</header> If you have certain domain names that server owners or resellers should not be allowed to create (such as sub-domains of your company's domain), then they can be listed in this field. Domains must be given as Perl-style regular expressions, so to deny any sub-domain under <i>foo.com</i> you should enter <i>.*\.foo\.com</i>. <p> <footer>