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6to4 at server side

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The aborted 6to4 effort bore an unexpected fruit. I discovered that Rimuhosting VPS latency to nearest was very, very low, so I gave it a try, as a simple way to have IPv6 in a VPS machine.

The configuration is very similar to OpenWRT 6to4, except that we don't need radvd, and servers tend to have a fixed IP, which makes things easier:

WANIP=$(ip -4 addr show dev eth0 | awk '/inet / {print $2}' \
	| cut -d/ -f1)
V6PREFIX=$(printf '2002:%02x%02x:%02x%02x' $(echo $WANIP | tr . ' '))
ip tunnel add tun6to4 mode sit ttl 255 remote any local $WANIP
ip link set tun6to4 mtu 1280
ip link set tun6to4 up
ip addr add $V6PREFIX:0::1/16 dev tun6to4
ip addr add $V6PREFIX:1::1/64 dev eth0
ip -6 route add 2000::/3 via :: dev tun6to4 

I passed the hint forward, and it can be seen in Rimuhosting page about IPv6.

You can access my IPv6-only home page The base address ( has both A and AAAA addresses, so it works for IPv4-only and IPv6-only clients. For dual-stack clients, it prefers IPv6 but some clients implement the "Happy Eyeballs" algorithm that falls back to IPv4 if latency in IPv6 is too high.

Provided your ISP is routing the anycast address (and I bet it is; even the Brazilian ISPs are doing it) this method could be used by any entity which wants to connect to IPv6 cloud. Just remember that you need an additional service to distribute IPv6 addresses, like radvd (shown in previous posts) or DHCPv6. And you need to set up a firewall for IPv6.

I'd say that a true tunnel like Hurricane Electric's would be better for a 'serious' environment (or if you need a fixed IPv6 range and does not have a fixed IPv4). In the other hand, 6to4 does not demand any account registration. Also, as ISPs improve their own IPv6 networks and upstream connections, 6to4 may offer lower latency (as happened in Rimuhosting).

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