Arefly

Disallow Japanese Language Comments in Your Blog. (Full Support with AJAX Comments Too!)
在你的部落格中禁止日文評論（? ?面支持AJAX評論提示）
Live Demo: <a href="http://www.arefly.com/no-japanese-comments/#respond" rel="nofollow ugc">Click Here</a> (Try Enter Some Japanese there)
<h4>Translators</h4>
<ul>
<li>Chinese, Simplified (zh_CN) – <a href="http://www.arefly.com/" rel="nofollow ugc">Arefly</a></li>
<li>Chinese, Traditional (zh_TW) – <a href="http://www.arefly.com" rel="nofollow ugc">Arefly</a></li>
<li>English (en_US) – <a href="http://www.arefly.com" rel="nofollow ugc">Arefly</a></li>
</ul>
If you have created your own language pack, or have an update of an existing one, you can send <a href="https://codex.wordpress.org/Translating_WordPress" rel="nofollow ugc">gettext PO and MO files</a> to <a href="http://www.arefly.com/about/" rel="nofollow ugc">Arefly</a> so that I can bundle it into No Japanese Comments. You can download the latest <a href="https://plugins.svn.wordpress.org/no-japanese-comments/trunk/lang/no-japanese-comments.pot" rel="nofollow ugc">POT file</a>.

No Japanese Comments

Disallow Japanese Language Comments in Your Blog. 在你的部落格中禁止日文評論

Web Guy

Dam Spam is a comprehensive spam protection plugin that blocks spam registrations, login attempts, comments, and contact form submissions. It provides multiple layers of protection including IP blocking, email validation, CAPTCHA challenges, and integration with third-party spam detection services.
How it Works
Dam Spam runs a series of configurable checks on registrations, logins, comments, and form submissions. When a submission is flagged as potentially suspicious, you can choose to block it outright or present a CAPTCHA challenge. Legitimate users are cached to speed up future submissions, while known spam sources are permanently blocked.
Features
<ul>
<li>Multiple Protection Layers – Block spam using IP lists, disposable email detection, and behavioral analysis</li>
<li>CAPTCHA Support – Integrate with Google reCAPTCHA or hCaptcha to challenge suspicious submissions</li>
<li>Third-Party API Integration – Connect with Akismet, Stop Forum Spam, BotScout, and other spam detection services</li>
<li>Customizable Challenges – Present challenges only to suspicious users while allowing legitimate users through</li>
<li>Allow and Block Lists – Maintain custom lists of allowed and blocked IPs, emails, and user IDs</li>
<li>Smart Caching – Cache known good and bad IPs to improve performance and reduce API calls</li>
<li>Comprehensive Logging – Track all blocked attempts and approved submissions for review</li>
<li>Custom Login/Registration Forms – Optional custom forms with built-in spam protection</li>
<li>User Management – Identify and manage inactive or suspicious user accounts</li>
</ul>
Configuration
After installation, go to the Dam Spam settings in your WordPress admin to:
<ol>
<li>Enable the protection types you need (registration, login, comments, contact forms)</li>
<li>Choose which spam detection methods to use (IP checks, email validation, third-party APIs)</li>
<li>Configure CAPTCHA settings if desired</li>
<li>Set up allow and block lists for your specific needs</li>
<li>Review logs to fine-tune your protection settings</li>
</ol>
Differences from Stop Spammers
Dam Spam is a fork of the Stop Spammers plugin with ongoing maintenance, bug fixes, and security improvements. While the core spam protection functionality remains similar, Dam Spam’s file and code structure has been significantly cleaned up and will continue to be further modernized.

Dam Spam

Comprehensive spam protection for WordPress registration, login, comments, and contact forms.

No Japanese Comments vs Dam Spam