jp2112

This plugin implements DNS prefetching per the Mozilla specification for the Firefox browser. Hopefully, other browsers will eventually support DNS prefetching.
See https://developer.mozilla.org/en-US/docs/Controlling_DNS_prefetching for more detail.
Disclaimer: This plugin is not affiliated with or endorsed by Mozilla.
<h3>If you need help with this plugin</h3>
If this plugin breaks your site or just flat out does not work, create a thread in the <a href="https://wordpress.org/support/plugin/dns-prefetch" rel="ugc">Support</a> forum with a description of the issue. Make sure you are using the latest version of WordPress and the plugin before reporting issues, to be sure that the issue is with the current version and not with an older version where the issue may have already been fixed.
Please do not use the <a href="https://wordpress.org/support/view/plugin-reviews/dns-prefetch" rel="ugc">Reviews</a> section to report issues or request new features.

DNS Prefetch

Adds dns prefetching meta tags to your site.

Imtiaz Ahmed

Matrixlab

MTX Email DNS Validator for Contact Form 7 prevents users from submitting contact forms with non-existent or invalid email addresses by performing DNS/MX record validation before form submission.
<h4>Features</h4>
Validation 
* DNS/MX Record Validation – Verifies email domains have valid MX records 
* SMTP Mailbox Verification – Advanced validation that checks if the specific email address/mailbox exists 
* Abstract API Integration – Comprehensive third-party email validation with quality scoring, risk assessment, and breach detection 
* Catch-All Domain Detection – Optionally reject domains that accept any email address (available in DNS+SMTP mode) 
* Disposable Email Detection – Block temporary/throwaway email addresses (via Abstract API) 
* Role-Based Email Detection – Identify generic addresses like info@, admin@, support@ (via Abstract API) 
* Three Validation Modes: 
 – DNS Only (Fast) – Validates domain can receive emails (~0.5s) 
 – DNS + SMTP (Thorough) – Validates both domain and specific mailbox (~2-5s) 
 – Abstract API (Advanced) – Comprehensive validation with quality scoring, risk assessment, and more 
* Per-Form Configuration – Configure validation settings for each CF7 form individually 
* Custom Error Messages – Set global or per-form error messages
Admin Interface 
* Tabbed Interface – Organized Settings and Tools tabs for better UX 
* Modern React Admin – Beautiful admin interface built with React 18 and Ant Design 5 
* Welcome Pointer – Helpful onboarding tooltip for first-time users 
* Import/Export Settings – Backup and migrate settings with JSON export/import 
* Cache Management – Clear DNS cache on demand from Tools tab 
* UI Preferences – Per-user interface settings (reset welcome pointer)
Performance & Data 
* Validation Logging – Track all validation attempts with detailed logs and statistics 
* Expandable Log Details – View comprehensive validation data including deliverability, quality scores, risk assessment, domain info, and breach history 
* DNS Caching – Improves performance by caching DNS lookups (24-hour default) 
* Data Cleanup Control – Choose whether to delete all plugin data on uninstall 
* Multiple Click Protection – Prevents duplicate requests from rapid button clicks
Developer Features 
* Extensible Hooks – Filters and actions for custom validation logic 
* REST API – Full REST API for settings and logs management 
* Translation Ready – Fully internationalized and localization-ready 
* WordPress Coding Standards – Follows WordPress PHP and JavaScript standards
<h4>Benefits</h4>
<ul>
<li>Reduce email bounce rates</li>
<li>Protect your domain reputation</li>
<li>Improve email deliverability</li>
<li>Prevent spam and fake submissions</li>
<li>Better data quality for marketing campaigns</li>
</ul>
<h4>Requirements</h4>
<ul>
<li>WordPress 6.2 or higher</li>
<li>PHP 8.1 or higher</li>
<li>Contact Form 7 plugin</li>
</ul>

MTX Email DNS Validator for Contact Form 7

Advanced email validation for Contact Form 7 using DNS/MX records and SMTP verification to prevent invalid email submissions.

DNS Prefetch vs MTX Email DNS Validator for Contact Form 7