Description of problem:
An increasing number of large providers (at least in germany) are assigning IPv6 addresses to newly assigned hosts. That's why fail2ban should get IPv6 Support as well, so tracking & banning will work with v6 addresses too.
No IPv6 support, a possible hack attempt from ipv6 addresses will be unnoticed by fail2ban. (as of 0.8.11-2.el6)
IPv6 support is available and working.
Please see for a possible patch at http://www.fail2ban.org/wiki/index.php/Fail2ban:Community_Portal#IPv6_Experimental_support
Even if marked as "experimental" it is working well, and solution is "easy" to migrate into package.
This might (partly) be related, but unmodified since 2012-03 https://bugzilla.redhat.com/show_bug.cgi?id=800694