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
Björn Persson