ipv6 confusion

[Aryeh M. Friedman]

I want to set my machine up to be on both IPv4 and IPv6.   I have read
the stuff on 6over4 and such and still a little confused on a few things:

1. The machine I want to do the tunneling on is behind a NAT'ed firewall
how do I reliabelly obtain the external IP of the firewall (dhcp
assigned from cable company)?

2. If the machine I want to do the tunneling with is the DMZ host for
the above FW do I need to add anything special to the FW's routing tables?

3. I am a little confused on how to pick the other end of the tunnel and
how do I configure it once the first 2 items are solved?... The
confusion comes from how is an arbitary (by me [with in the restrictions
in stf(4)]) selected IPv6 IP supposed to be routable when IPv4 forces 
me to use the one assigned to me by my upstream router?

-- 
Aryeh M. Friedman
Developer, no business friendly
http://www.flosoft-systems.com