Heads up: impending IPv6 Test Day

[Richard W.M. Jones]

On Thu, Jun 02, 2011 at 06:00:44PM +0200, Björn Persson wrote:
> Daniel P. Berrange wrote:
> > On Thu, Jun 02, 2011 at 04:40:10PM +0100, Richard W.M. Jones wrote:
> > > The Linux machines on my LAN appear to have acquired IPv6 addresses, eg:
> > > 
> > > $ ip addr show eth0
> > > 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
> > > state UNKNOWN qlen 1000
> > > 
> > >     link/ether 00:e0:81:74:02:28 brd ff:ff:ff:ff:ff:ff
> > >     inet 192.168.0.128/24 brd 192.168.0.255 scope global eth0
> > >     inet6 fe80::2e0:81ff:fe74:228/64 scope link
> > >     
> > >        valid_lft forever preferred_lft forever
> > > 
> > > but pinging them gives me strange errors:
> > > 
> > > $ ping6 fe80::2e0:81ff:fe74:228/64
> > > unknown host
> > > $ ping6 fe80::2e0:81ff:fe74:228
> > > connect: Invalid argument
> > > $ ping6 fe80::2e0:81ff:fe74
> > > connect: Invalid argument
> > 
> > Anything with an  fe80:: prefix is a link local address, which
> > is only unique within the scope of a single LAN segment. Thus
> > if you want to send traffic to such addresses, you need to specify
> > the NIC to send the traffic out from. The vast majority of apps
> > using sockets have no way to let you do this.
> 
> Ping6 has a way though:
> 
> $ ping6 -I eth0 fe80::200:24ff:fec9:2e0c
> PING fe80::200:24ff:fec9:2e0c(fe80::200:24ff:fec9:2e0c) from 
> fe80::21e:8cff:fecf:cde5 eth0: 56 data bytes
> 64 bytes from fe80::200:24ff:fec9:2e0c: icmp_seq=1 ttl=64 time=1.69 ms
> 64 bytes from fe80::200:24ff:fec9:2e0c: icmp_seq=2 ttl=64 time=0.263 ms

But that's not so useful if no other programs can use these addresses.
Is there a way to assign "proper" addresses?  Just run radvd and
configure it with a random prefix?

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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