[Eric]

It is possible. I thought I saw a mod for it here but I cannot seem to find it atm. You could make a plugin to block certain extensions/domains.

This has not been tested, but something like:

Hook location: register_addmember_process
PHP Code:

PHP Code:

    $emailcheck = @explode('@', $vbulletin->GPC['email']);
    $emailcheck = $emailcheck[1];

    if (strpos($emailcheck, 'domain.edu') === false)
    {
        $userdata->error('invalidemail');
    }