codicone

The whitelist/blacklist plugin gives you a strong layer of security for your website because not only does the plugin limits unauthorized user access to your site but also creates a log. The log helps to create new blacklist entries. The increase in your blacklist entries means a decrease in spam and security threats. So it is a great safety measure to start with.
It is a very handy plugin that you can add to your WordPress site for added security. It helps you to tailor your preferences about which email addresses you want to allow for registration on your site.
You can create a list of all email addresses or email domains that you wish to receive registrations. On the other hand, you can add a list for blacklist domains to not allow any registration from specific domains. Blacklisting is time-saving because most of the time you have already figured where the spam comes from. So you close those doors already. It is relatively safe also because you are not risking anything prospective.
<h4>Compatible With</h4>
<ul>
<li>WooCommerce</li>
<li>bbpress</li>
<li>buddypress</li>
<li>Profile Builder</li>
<li>WP User Frontend</li>
<li>User Registration</li>
<li>Ultimate member</li>
</ul>

Blacklist & Whitelist Domains for Registration

The whitelist/blacklist plugin gives you a strong layer of security for your website because not only does the plugin limits unauthorized user access  …

jamiewilson

Gatekeeper allows administrators to take a WordPress site offline quickly and easily while leaving it fully accessible to administrators and other authorized users. Site visitors will be shown or redirected to a specified offline page. An optional blacklist can be used for permanent bans.
** Features **
<ul>
<li>Visitors can either be redirected to an existing non-WordPress offline page (using http 302 temporary redirect) or WordPress pages can be temporarily replaced with the offline page.</li>
<li>Logged in admins can be whitelisted</li>
<li>The current admin’s IP address can be automatically whitelisted</li>
<li>An IP-based whitelist that can accept specific IP addresses, wildcards, and ranges</li>
<li>A basic IP-based blacklist that redirects blacklisted IPs to a specified page (not to be used for security)</li>
<li>A notifier that appears on administrator pages when the site is offline</li>
</ul>

Gatekeeper

Gatekeeper allows administrators to take a WordPress site offline while leaving it accessible to authorized users for maintenance, testing, etc.

Blacklist & Whitelist Domains for Registration vs Gatekeeper