Limit user registrations to domain names on a whitelist.
For an internal or private WordPress installation you may want to place restrictions on who can register a user account. This plugin allows the administrator to specify a 'whitelist' of domain names and restricts registrations to email addresses from those whitelisted domains.
Please Note: This plugin is only tested on PHP5 and may not work on earlier versions.
Thanks to RedCat Co for sponsorship of initial development of this plugin