FasterThemes

Quick Whois WordPress Plugin Shows whois information of the provided domain name. You can use Widget in the sidebar or you can also use Shortcode in the pages/posts.
<a href="http://whois.fasterthemes.com/" rel="nofollow ugc">DEMO of Quick Whois plugin</a>
Features:
<ul>
<li>You can use this plugin in your sidebar by dragging and dropping “Quick Whois” Widget.</li>
<li>You can use this in any specific page/post by putting shortcode [quick_whois].</li>
<li>This plugin converts your website into a whois data provider website in a few seconds !</li>
</ul>
<h3>License and Copyrights for Resources used in this plugin</h3>
i) We have used phpwhois.org php script from this website http://www.phpwhois.org Copyright which is a free software and we are allowed to redistribute it and/or 
modify it under the terms of the GNU General Public License v2.
<pre><code>For any help you can mail us at support[at]fasterthemes.com
</code></pre>

Quick Whois

Quick Whois Plugin Shows Whois information of the provided domain name.  You can do this using Widget/Shortcode.

ppatux

Simple IPv6 detector widget for WordPress to show if user is connecting with IPv6 or IPv4.
Additionaly, it makes a link to a whois service with the ip address.
It was born because of my own blog. I needed to include a little box that shows users ip and different messages depending on the ip version.
The idea behind this is to promote and leave a way to discover and make sense about the ipv4 address space limits.

IPv6 Detector

Simple IPv6 detector widget for WordPress to show if user is connecting with IPv6 or IPv4.

Quick Whois vs IPv6 Detector