Firdaus Zahari

This plugin allows you to track all user devices used when logging in to your site. The user agent, login date/time, and logout date/time (if the users log out from the site) are tracked automatically and persisted into the database for later viewing.
You can find a list of all login devices available under the Users > Login Devices submenu.

FS Login Devices

Track and display all users devices used during authentication process

This plugin can detect information such as country name, web browser and operating system from your commenters and then displays them on your comment section or anywhere you like.
Features:
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Detects and shows commenter?s country flag, web browser and operating system automatically
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Supports many web browsers and operating systems: major desktop browsers, antiquated browsers, blogging software (for trackbacks and pingbacks), text based browsers, various PDAs and cell phones.
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Uses a binay file for IP to country resolution and supports database sources from Webhosting.info – Software77.net
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The returned string can be configed as a template to suite your theme
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<h3>Credits</h3>
Especially thanks to
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<li>
<a href="http://priyadi.net/" title="Priyadi Iman Nurcahyo" rel="nofollow ugc">Priyadi Iman Nurcahyo</a> for his <a href="http://priyadi.net/archives/2005/03/29/wordpress-browser-detection-plugin/" title="WordPress Browser Detection Plugin" rel="nofollow ugc">WordPress Browser Detection Plugin</a>
</li>
<li>
<a href="http://firestats.cc/" title="Omry Yadan" rel="nofollow ugc">Omry Yadan</a> for his <a href="http://firestats.cc/wiki/EasyIP2Country" title="Easy IP2Country" rel="nofollow ugc">Easy IP2Country </a> plugin
</li>
</ul>

Comment Info Detector

Enables you to detect your commenter's info and show their country flag, web browser, operating system automatically.

FS Login Devices vs Comment Info Detector