Re: [gentoo-user] ipv6 problem with ping6

[Michael Mol]

Grant Edwards wrote:
> I've enabled ipv6 support in my kernel and it appears to be working on
> the "lo" interface:
>
>    # ip -6 addr show lo
>
>    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436
>        inet6 ::1/128 scope host
>           valid_lft forever preferred_lft forever
>
>    # ping6 -c3 ::1
>
>    PING ::1(::1) 56 data bytes
>    64 bytes from ::1: icmp_seq=1 ttl=64 time=0.022 ms
>    64 bytes from ::1: icmp_seq=2 ttl=64 time=0.021 ms
>    64 bytes from ::1: icmp_seq=3 ttl=64 time=0.021 ms
>
>    --- ::1 ping statistics ---
>    3 packets transmitted, 3 received, 0% packet loss, time 1998ms
>    rtt min/avg/max/mdev = 0.021/0.021/0.022/0.003 ms
>
> And the other interfaces all have link-local addresses:
>
>    # ip -6 addr show eth1
>    3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
>        inet6 fe80::216:17ff:fe84:a7b3/64 scope link
>           valid_lft forever preferred_lft forever
>
> But I can't ping6 any of the "real" interfaces (or any external
> address):
>
>    # ping6 -c3 fe80::216:17ff:fe84:a7b3
>
>    connect: Invalid argument
>
> Why can I ping "lo" at ::1 and not "eth1" at fe80::216:17ff:fe84:a7b3?
>
> I'm guessing there might other packages I have to re-emerge with the
> ipv6 use flag. But, I do not want to rebuild everything capable of
> supporting ipv6, since there are only a few selected programs that
> I'll be using with ipv6.  I thought I might have to rebuild glibc, but
> it doens't list ipv6 as one of it's use flags.
>
> Any hints?
>

ping6 -c3 fe80::216:17ff:fe84:a7b3%eth0

Link-local addresses are only valid at the link-level scope, and you
have to specify which link you're referring to. Global-scope addresses
don't have the same limitation.

Also, for fun, try this:
ping6 -c3 ff02::1%eth0