Date: Tue, 12 Aug 2008 14:53:24 +0200 From: Max Laier <max@love2party.net> To: freebsd-stable@freebsd.org Cc: Mathieu Arnold <mat@freebsd.org>, Pete French <petefrench@ticketswitch.com> Subject: Re: neighbor discovery problem Message-ID: <200808121453.24383.max@love2party.net> In-Reply-To: <6C5A5164866ACB760C1B37CA@andromede.in.absolight.net> References: <E1KSreE-000ATd-NT@dilbert.ticketswitch.com> <6C5A5164866ACB760C1B37CA@andromede.in.absolight.net>
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On Tuesday 12 August 2008 13:35:33 Mathieu Arnold wrote:
> +-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,
^------^
There is your problem. You have all three hosts connected to the same
broadcast domain? Disable redirects or separate the domains using VLAN or
similar - otherwise the gateway will get smart and try to avoid work.
> 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 :-)
--
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