Okay, I said I would do it, but it took someone else beating me to it to get me to get things going.

Andy managed to find out that 6to4 is definitely the way to go if you have a static IPv4 address. There's lots of anycast servers that handle being the endpoint, so it's much more distributed than the other tunnel brokers. And it's natively supported and easy to setup.

Here's the CentOS 4/RHEL 4 config:

/etc/sysconfig/network

NETWORKING_IPV6=yes

IPV6_DEFAULTDEV=tun6to4

/etc/sysconfig/network-scripts/ifcfg-eth0

IPV6INIT=yes

IPV6TO4INIT=yes

One ifdown eth0 && ifup eth0 and you're good-to-go.

Unfortunately CentOS 4 doesn't support stateful connections in ip6tables (which is the iptables-ipv6 package), so after copying /etc/sysconfig/iptables to /etc/sysconfig/ip6tables I had to remove any stateful tracking for now (iptables-ipv6 is 1.3.5 in CentOS5, so after upgrading I should be good).

And the proof:

$ ping6 www.kame.net

PING www.kame.net(orange.kame.net) 56 data bytes

64 bytes from orange.kame.net: icmp_seq=0 ttl=51 time=236 ms

64 bytes from orange.kame.net: icmp_seq=1 ttl=51 time=236 ms

64 bytes from orange.kame.net: icmp_seq=2 ttl=51 time=236 ms

64 bytes from orange.kame.net: icmp_seq=3 ttl=51 time=235 ms

Argo is 2002:423b:6d88::1 (and hopefully www.silfreed.net works from that).

On the home side, I decided to go with Hurricane Electric's IPv6 Tunnel Broker. I'm still waiting for my tunnel to come up so I haven't configured radvd yet (well, I have, but it doesn't work), but the configuration is still very simple.

/etc/sysconfig/network

NETWORKING_IPV6=yes

IPV6_DEFAULTDEV=sit1

And then add /etc/sysconfig/network-scripts/ifcfg-sit1 (you can't use sit0)

DEVICE=sit1

BOOTPROTO=none

ONBOOT=no

IPV6INIT=yes

IPV6TUNNELIPV4=HESupplied-ServerIPv4address

IPV6ADDR=HESupplied-ClientIPv6address

So very shortly I'll be on my way to IPv6 as well (just a tad later than others ;-).