Masoud Binaei

This plugin allow WordPress to detect Real visitors IP Address when WordPress is behind of Reverse Proxy, Load Balancer or CDN. 
It will start working as soon as you activate it.
It is also compatible:
<ul>
<li>Cloudflare.com</li>
<li>geniusguard.com</li>
<li>central-hosting.com</li>
<li>incapsula.com</li>
<li>sucuri.net</li>
<li>barracuda.com</li>
<li>f5.com And Other…</li>
</ul>

Real IP Detector

Very good

This plugin allow WordPress to detect Real visitors IP Address.

proninyaroslav

Adds IP from comment that marked as spam to standard WordPress blacklist. Comments already marked as spam are not added to the list.

Spam to blacklist

Adds IP from comment that marked as spam to standard WordPress blacklist.

Real IP Detector vs Spam to blacklist