IPv6 in Ubuntu Natty Narwhal

by Jeff Loughridge

I always considered Linux to be a leader in IPv6; the first IPv6 code was added to the kernel in 1996. I’ve recently noticed that the several Linux distributions do not support IPv6 in a way that allows typical users to connect to an IPv6 network. Let’s examine Ubuntu Natty Narwhal.

Natty does not activate IPv6 by default and requires special configuration. Windows 7 has better IPv6 support out of the box than Ubuntu Natty Narwhal. Surprising? An average user can obtain connectivity to the IPv6 Internet using default configuration in Windows 7.

Activating IPv6 in Natty can be done using NetworkManager  (GUI tool) or  manually editing /etc/network/interfaces. There are limitations. Even though the ISC DHCP client supports DHCPv6, the end station will not request a nameserver. For /etc/network/interfaces, you’d think that obtaining an IPv6 address through DHCPv6 would be simple: add an “iface ethx inet6 dhcp” line. Unfortunately, this won’t work in Natty. I am using a hack. I assign a ULA address and then use post-up to execute dhclient.

iface eth0 inet6 static
address fc00::1
netmask 64
post-up /sbin/dhclient -6 eth0

I figured this out through trial and error; this method is not fitting for the average user.

The next Ubuntu release is Oneiric Ocelot. IPv6 should be enabled by default in it. I am testing an alpha build that doesn’t yet have a fix for enabling DHCPv6 in /etc/network/interfaces. Let’s hope this gets fixed prior to release.

After encountering problems, I found that Tore Anderson opened bugs in April 2011. I recommend reading Tore’s exchange with the developer on enabling IPv6 by default. Tore tries to correct the mindset that IPv6 is only needed for power users.

The thread is here.

The bug for the missing DNS server in DHCPv6 is here.


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