In the config you can disallow domains
This is the opposite of $_CONF['allow_domains'] (see above): A list of domain names that are not allowed in email addresses of new users. Note that this list is always used, even when the user submission queue has been switched off. Again, regular expression can be used. Example disallow email addresses with a certain domain name and from any ".edu" domain: 'somebaddomain.com,\.edu$'
I set a coma separated domain name list in the config but users from one site are still able to register. (I will investigate more tomorrow on this issue).
Ben
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