Re: [IPv6] Something I don't understand

[BERTRAND Joël <joel.bertrand%systella.fr@localhost>]

RVP a écrit :
> On Thu, 7 Sep 2023, BERTRAND Joël wrote:
> 
>> But from LAN, IPv6 public network is unreachable. For example:
>> hilbert:[~] > ping6 www.google.fr
>> PING www.google.fr(par10s39-in-x03.1e100.net (2a00:1450:4007:807::2003))
>> 56 data bytes
>>
>>     On legendre (NetBSD server), tcpdump on wm2 (public interface) shows:
>> legendre# tcpdump -i wm2 -p ip6
>> 09:28:19.696443 IP6 PREFIX:a10:d65d:64ff:feb4:9a3b >
>> par10s39-in-x03.1e100.net: ICMP6, echo request, seq 16, length 64
>> 09:28:20.720469 IP6 PREFIX:a10:d65d:64ff:feb4:9a3b >
>> par10s39-in-x03.1e100.net: ICMP6, echo request, seq 17, length 64
>>
>>     Thus, icmp packets received from lan side are sent to public
>> interface,
>> but there is no answer.
>>
> 
> Maybe it's an ISP issue? Can you ping your machines from the outside
> using, say,
> an SDF.org account? Check if packets arrive on wm2 on legendre when you do
> this.
> 
> -RVP

	Maybe. This morning, IPv6 connection runs better as inbound and
outbound and I have received a mail from my ISP where he has written
that IPv6 gateway configuration has changed.

	Now, both Linux and NetBSD can send and receive IPv6 packets but
workstations on LAN cannot use IPv6 through NetBSD server.

	On Linux side, I have written a long time ago in /etc/network/interfaces:

iface wan0 inet6 static
        address PREFIX:a00::2
        netmask 64
        gateway PREFIX:a00::1
        pre-down /sbin/ip -6 route del unreachable PREFIX:a00::/56
        post-up /sbin/ip -6 route add unreachable PREFIX:a00::/56

as my ISP routes PREFIX:a00::/56 network

	When I try a ping6 www.google.fr from LAN, NetBSD's wan interface sends:

09:38:32.261784 IP6 PREFIX:a10:d65d:64ff:feb4:9a3b >
par10s21-in-x03.1e100.net: ICMP6, echo request, seq 1, length 64
09:38:33.277892 IP6 PREFIX:a10:d65d:64ff:feb4:9a3b >
par10s21-in-x03.1e100.net: ICMP6, echo request, seq 2, length 64

	I suppose NetBSD cannot route ICMP6 answer as www.google.fr sends its
answer to PREFIX:a10:d65d:64ff:feb4:9a3b and WAN address is
PREFIX:a00::/64 (PREFIX:a10::/64 is only on LAN side). How can I
configure WAN interface to accept IPv6 packets for LAN ?

	Best regards,

	JB