neighbor discovery problem

[Mathieu Arnold]

+-le 12.08.2008 12:02:42 +0100, Pete French a dit :
|> Since I added IPv6 to my network, and started really using it, I'm seeing
|> some strange things happening.
|> 
|> For instance, I'm on machine 2a01:678:1:443::443, and I do :
|> 
|> $ traceroute6 -n 2a01:678:100:2::
|> traceroute6 to 2a01:678:100:2:: (2a01:678:100:2::) from
|> 2a01:678:1:443::443, 64 hops max, 12 byte packets
|>  1  2a01:678:1:443::  0.636 ms  0.602 ms  0.525 ms
|>  2  2a01:678:1:443::  2999.665 ms !A  2999.636 ms !A  2999.680 ms !A
|> 
|> 2a01:678:1:443:: is it's default gateway, and is also directly connected to
|> 2a01:678:100:2::, but it does not seem to be able to contact it.
| 
| What are your prefix lengths on the various interfaces, and does
| 2a01:678:100:2:: have a route back to 2a01:678:1:443::443 ? If you
| can show us the config on the interfaces of the three machines then
| we might be able to get a better idea. I am imagining how you have these
| three boxes connected in my head, but nothing beats an explanation plus
| the config :-)

Hum, 2a01:678:1:443::443 is a /64, and 2a01:678:100:2:: is on a /48, both
have the "same" gateway, that is, the same box, which has :
        inet6 2a01:678:1:443:: prefixlen 64
        inet6 2a01:678:100:: prefixlen 48

The problem I'm seeing is that before I ping the machine from the gateway,
all ndp -a says about this machine is :

2a01:678:100:2::                     (incomplete)         em0 1s        I  3

when I ping it from the first host, I see :

2a01:678:1:443::443 > 2a01:678:100:2::: ICMP6, echo request, seq 0, length 16
fe80::207:e9ff:fe0e:dead > ff02::1:ff00:0: ICMP6, neighbor solicitation, who
has 2a01:678:100:2::, length 32
fe80::207:e9ff:fe0e:dead > 2a01:678:1:443::443: ICMP6, redirect,
2a01:678:100:2:: to 2a01:678:100:2::, length 104
fe80::2b0:d0ff:fee1:c05f > fe80::207:e9ff:fe0e:dead: ICMP6, neighbor
advertisement, tgt is 2a01:678:100:2::, length 32
fe80::207:e9ff:fe0e:dead > ff02::1:ffe1:c05f: ICMP6, neighbor solicitation,
who has fe80::2b0:d0ff:fee1:c05f, length 32
fe80::2b0:d0ff:fee1:c05f > fe80::207:e9ff:fe0e:dead: ICMP6, neighbor
advertisement, tgt is fe80::2b0:d0ff:fee1:c05f, length 32

and when I ping it from the gateway, I see :

2a01:678:100:25:: > 2a01:678:100::: ICMP6, neighbor solicitation, who has
2a01:678:100::, length 32
2a01:678:100:: > 2a01:678:100:25::: ICMP6, neighbor advertisement, tgt is
2a01:678:100::, length 24
2a01:678:100:: > ff02::1:ff00:0: ICMP6, neighbor solicitation, who has
2a01:678:100:2::, length 32
2a01:678:100:2:: > 2a01:678:100::: ICMP6, neighbor advertisement, tgt is
2a01:678:100:2::, length 32

And I don't understand why there's a difference, and why when the packets
don't come from the gateway, the neighbor solicitation goes up wrong and does
not work.

|> Maybe I'm doing something wrong, but, well, I can't seem to find ou what.
|> 
|> 2a01:678:1:443::443 is a 7.0
|> 2a01:678:1:443::    is a 6.2
|> 2a01:678:100:2::    is a 6.0
| 
| I've used all of those with IPv6 and they work fine, it's most likely
| a small config problem. I had a lot of frustrations with IPv6 when I
| started using it - though now it is working I wouldn't be without it.

Well, I'm certain it must be some stupid configuration problem, but, well, I
can't seem to find it :-)

-- 
Mathieu Arnold
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 195 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20080812/0fdd7f6a/attachment.pgp