Prevent email addresses and email domains from registering

Since Version 2.2.0 of Discussion Board, you can block specific email addresses and domains from registering on your site. Anyone trying to register using a blacklisted email will find that their registration attempt fails silently. To block emails, go to Discussion Board > Settings > User tab and enter an email address in the ‘Email blacklist’ field, e.g. dave@spammer.com will cause this email address to fail registration. If you want to block an entire domain, enter the domain preceded by the ‘@’ symbol: e.g. @spammer.com will cause all email addresses from the spammer.com domain to fail registration. Enter one address per line.