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ipv6

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At the moment I'm planning on trying to get Tardis some IPv6 connectivity. Since Tardis has at least one public IP address it is possible to set up 6to4 tunnel to the IPv6 network or a manually configured tunnel to the core JANET network (which is IPv6 enabled). Ideally it would be great if we had native IPv6 access through ed_lan but this does not appear to be supported at the present time.

The we now have a 6to4 tunnel running on ace which provides IPv6 connectivity as well as packet filtering for the rest of the Tardis network. IPv6 autoconfiguation could be then be provided through either quagga or radvd, though static configuration might be more suited for the time being.

Getting Connected

JANET currently supports 4 ways to gain IPv6 connectivity.

  1. Native IPv6 connections where available
  2. Manually-configured IPv6 tunnels
  3. 6to4 tunnels and 6to4 relay
  4. IPv6 tunnel broker/server

Native IPv6 connection

This is the holy grail of IPv6 connectivity and where everything should eventually end up. The JANET core has been IPv6 enabled for a few years but the regional networks have been a bit slower off the mark. One of the services provided by SuperJANET5 is native IPv6 traffic and this has been identified by both EaStMAN (see here) and EdLAN (see here) as target objectives for 2006/2007 though I can't seem to locate any further information at present.

Manually-configured IPv6 tunnels

JANET provides an experimental IPv6 service which lets sites create a 6in4 tunnel to the JANET core. This is probably the most preferable option at the moment since it would mean Tardis would be allocated an IPv6 address out of the JANET IPv6 space (2001:0630::/32). Tunnels are manually configured so all requests have to be made to the JANET Technical Administration Group.

6to4 tunnels and 6to4 relay

An alternative to a manual tunnel is the semi-automatic 6to4 protocol which allocates a IPv6 address based on the public IPv4 address (in the 2002::/16 range). The disadvantage of this method is that while it allows 6to4 hosts to communicate quite effectively there is no way to contact the native IPv6 network. Hence you need to use a 6to4 relay to connect to the native IPv6 network. JANET provides a relay at 192.88.99.1 for hosts on the JANET network.

You can specify reverse DNS servers for a 6to4 network just by visiting NRO 6to4reverse form and entering the details.

IPv6 tunnel broker/server

The final way is to use a broker service to connect. While this method is relatively easy to set up (See the JANET Broker Service) and has the advantage of being able to use both IPv6-over-IPv4 tunnels and IPv6-over-UDP tunnels (which can get around some firewall/NAT issues) it's more designed for end users connectivity. For more permanent connections one of the other methods is preferred.

Tardis Configuration

At the moment we are using 6to4 with the external router IP address of ace (129.215.160.171) meaning that it is allocated the network range 2002:81d7:a0ab::/48. Tardis' name servers have been specified at NRO so reverse DNS should work on these addresses (b.a.0.a.7.d.1.8.2.0.0.2.ip6.arpa).

External Network

The external network is allocated 2002:81d7:a0ab:0::/64. This network basically consists of just ace's external interface (eth0) at 2002:81d7:a0ab::1 and exists mainly for routing purposes.

Internal network

The internal network is allocated 2002:81d7:a0ab:1::/64 with the gateway being ace's internal interface (eth1.3) at 2002:81d7:a0ab:1::1.

To assign an IP to a host just edit /etc/network/interfaces and add:

iface eth0 inet6 static
    address 2002:81d7:a0ab:1::**<SOMETHING>**
    netmask 64
    gateway 2002:81d7:a0ab:1::1

Firewall

Like IPv4 traffic IPv6 traffic is filtered. At the moment the only traffic that can be routed through the firewall is IMCPv6 (see the tardis-IPv6firewall script). So you can ping, but that's about it. Other traffic will be added when I have time to sit down and work out what traffic is allowed to/from each host.

See Also

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