Jake Jackson

<p>If you like total control of the comments on your WordPress blog without having any extra overheads (like you get with 3rd party spam prevention software) then this is a great tool for you.</p>
<h4>Features</h4>
<ul>
<li>Automatically placed IP address on comments blacklist if administrator marks comment as spam</li>
<li>Will remove IP address from comments blacklist if spam item is marked as ‘not spam’</li>
<li>When activated, will review all spam comments and place the spammers IP address on the comments blacklist.</li>
</ul>
<h4>Support</h4>
<p><a href="http://www.blueliquiddesigns.com.au/index.php/wp-automatic-spam-blacklister/" rel="nofollow ugc">All support is provided through the plugin developer’s website</a>.</p>


WP Spam Blacklister

The WP Spam Blacklister is a simple spam-prevention plugin that adds the IP address of a marked spam post on Wordpress' comments blacklist.

Matt Harrison

Hall

CrossPeak

TimBHowe

<p>The Email Blacklist Add-on for Gravity Forms was built to help block submissions from users with generic or competitors email addresses. Prevent the user from processing the form and stop non-qualified leads from being collected.</p>
<p>This plugin allows site admins to create a list of domains that if used in an email field on a Gravity Form it will cause a validation error and block the submission. A default email blacklist and validation message can be created to use across all email fields. These default settings can be overridden on a per email field basis.</p>
<p>Global settings can be added on ‘Forms’ > ‘Settings’ > ‘Email Blacklist’. To add settings to an individual email field, select the field and navigate to the ‘Advanced Settings’ tab.</p>
<p>This plugin works by blocking either individual email addresses (ex. jsmith@gmail.com), email address domains (ex. gmail.com), and/or email address top-level domains (ex. *.com).</p>
<p>Feel free to contribute on <a href="https://github.com/crosspeaksoftware/gravity-forms-email-blacklist" rel="nofollow ugc">github</a>.</p>
<h3>Instructions</h3>
<h3>Global Blacklist Settings</h3>
<p>Once set up, these settings will be used on all email input fields across all the Gravity Forms used on the site. They can be overridden by the individual email blacklist settings below.</p>
<ol>
<li>Once Logged into your site navigate to ‘Forms’ > ‘Settings’ > ‘Email Blacklist’</li>
<li>In the ‘Global Blacklisted Emails’ input enter a comma separated list of blacklisted domains (ie. hotmail.com), email addresses (ie. user@aol.com), and/or include the wildcard notation to block top-level domains (ie. *.com). This setting can be overridden on individual email fields in the advanced settings.</li>
<li>In the ‘Global Validation Message’ input enter a default error message if a blacklisted email is submitted. This setting can be overridden on individual email fields in the advanced settings.</li>
<li>Select the ‘Global Invalid Entry Procedure’ to determine how the blacklisted submissions should be handled, with validation error or collected and marked as spam.</li>
<li>Click the ‘Update Settings’ button to save the settings.</li>
</ol>
<h3>Individual Email Input Blacklist Settings</h3>
<p>Once set up these settings will be used on this form only and in place of the global blacklist settings above.</p>
<ol>
<li>Once Logged into your site navigate to the Gravity Form you would like to update.</li>
<li>Add or update an existing email input field on the form.</li>
<li>Go to the ‘Advanced Settings’ tab for the ‘Blacklisted Emails’ input.</li>
<li>In the ‘Blacklisted Emails’ input enter a comma separated list of blacklisted domains (ie. hotmail.com), email addresses (ie. user@aol.com), and/or include the wildcard notation to block top-level domains (ie. *.com). This will override the globally defined blacklisted emails setting. Enter ‘none’ to bypass the global setting and allow all email addresses.</li>
<li>In the ‘Blacklisted Emails Validation Message’ input enter an error message if a blacklisted email is submitted. This will override the globally defined error message.</li>
<li>Select the ‘Invalid Entry Procedure’ to determine how the blacklisted submissions should be handled, with validation error or collected and marked as spam.</li>
<li>Click the ‘Save Form’ button to save the settings.</li>
</ol>
<h3>Additional Resources</h3>
<ul>
<li><a href="https://docs.gravityforms.com/category/getting-started/" rel="nofollow ugc">Gravity Forms Documentation – Getting Started</a></li>
<li><a href="https://docs.gravityforms.com/email/" rel="nofollow ugc">Gravity Forms Documentation – Email Input Fields</a></li>
<li><a href="https://docs.gravityforms.com/spam/" rel="nofollow ugc">Gravity Forms Documentation – Fighting Spam</a></li>
</ul>


Gravity Forms Email Blacklist

Exactly what I needed - works like a charm.

Thanks @cleverpixel

Brilliant

Add-on for Gravity Forms to create a Blacklisting of specific emails or domains for the Email input field to throw a validation error or mark as spam.

WP Spam Blacklister vs Gravity Forms Email Blacklist