6tunnel allows you to use services provided by IPv6 hosts with IPv4-only applications and vice-versa. It can bind to any of your IPv4 (default) or IPv6 addresses and forward all data to IPv4 or IPv6 (default) host. For example

6tunnel -1 6668 irc6.net 6667

will be enough to connect to IPv6 irc server with

irc foobar localhost:6668

If you don't wish to run 6tunnel every time you want to show your :c001: or :dead: IPv6 address on IRC, you can use -i parameter, which makes 6tunnel ask your client for specified password. Just run

6tunnel -i dupa.8 31337 irc6.net 6667

and then type

irc foobar localhost:31337:dupa.8

If your IRC server requires you to send password, specify it with -I parameter -- after successful proxy authentication 6tunnel will send it to the server.

6tunnel can also be used as a tunnel for all other combinations of IPv4 and IPv6 endpoints. If remote host doesn't have any IPv6 addresses, 6tunnel will use the IPv4 one. In other cases, use -4 parameter which makes IPv4 address the preffered one. For IPv6-to-any tunnels use -6 which makes 6tunnel bind to IPv6 address.