Sometime potentially for the fwknop 2.1 release we should add full IPv6 support to both the fwknop client and fwknop server. A start was made on this for the client with this commit: http://www.cipherdyne.org/cgi-bin/gitweb.cgi?p=fwknop.git;a=commitdiff;h=6f79b6fb04090c53bca9abe53fc15e13786587da;hp=31ef94024cea1edb3024c9f78efa30794aa81264