Re: I need help configuring IPv6

> On Feb 23, 2022, at 23:41, Kenyon Ralph <[email protected]> =
wrote:
>=20
>>=20
>> On Feb 23, 2022, at 21:40, Nathan Van Ymeren <[email protected]> =
wrote:
>>=20
>> =EF=BB=BFOn Wed, Feb 23, 2022 at 8:24 PM Andika Triwidada =
<[email protected]> wrote:
>>>=20
>>>=20
>>>=20
>>>> On Thu, Feb 24, 2022 at 10:58 AM Nathan Van Ymeren =
<[email protected]> wrote:
>>>>=20
>>>>=20
>>>> The relevant portion of /etc/network/interfaces is:
>>>>=20
>>>> iface eno1 inet6 static
>>>>      address 2604:xxxx:xxxx:xxxx::2/64
>>>>      gateway 2604:xxxx:xxxx:xxxx::1
>>>>=20
>>>> As far as I can tell from reading the debian wiki and whatever =
else,
>>>> it should work like this, but even ping6'ing the gateway gives =
"ping6:
>>>> connect: Network is unreachable".  I can ping the gateway on its
>>>> link-local (fe80) address, but that's all I can do.
>>>>=20
>>>> Please help!
>>>>=20
>>>=20
>>> Hi Nathan,
>>>=20
>>> I think the first important step is to ensure that the gateway =
pingable
>>> at its 2604:xxxx:xxxx:xxxx::1 address, both from your computer and =
from the internet.
>>>=20
>>> Regards,
>>> Andika
>>>=20
>>=20
>> Sigh.
>>=20
>> It seems that the missing piece of the puzzle was this:  You can't
>> just add a default route (apparently).  You have to first add the
>> route to a specific interface.  It's not clear to me if this is
>> universally true, or just a consequence of something specific to my
>> setup (the server in question has multiple NICs).
>>=20
>> The tl;dr is that it's necessary for me to do the following in order:
>>=20
>> # ip -6 route add blah:blah::1 dev eno1
>> # ip -6 route add default via blah:blah::1
>>=20
>> where blah:blah::1/64 is the address my datacenter gave me for the v6
>> gateway router.
>>=20
>> I wish this had been more clearly laid out in the umpteen different
>> wikis and tutorials I've tried to follow.
>=20
> That=E2=80=99s not documented because it=E2=80=99s not normal to have =
to add such a route. The kernel automatically adds that route. There is =
something wrong with your configuration. If you don=E2=80=99t obfuscate =
the information, we might be able to tell what=E2=80=99s wrong.

I suppose v6 addresses aren=E2=80=99t really private.  The server is on =
2604:5800:0:1f::2 and the gateway I was given is 2604:5800:0:1f::1

# route -A inet6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref =
Use If
localhost/128                  [::]                       U    256 2     =
0 lo
2604:5800:0:1f::1/128          [::]                       U    1024 1    =
 0 eno1
2604:5800:0:1f::2/128          [::]                       U    256 2     =
0 eno1
fe80::/64                      [::]                       U    256 1     =
0 eno1
[::]/0                         2604:5800:0:1f::1          UG   1024 21   =
  0 eno1
localhost/128                  [::]                       Un   0   27    =
 0 lo
2604:5800:0:1f::2/128          [::]                       Un   0   10    =
 0 eno1
fe80::/128                     [::]                       Un   0   3     =
0 eno1
fe80::28c:faff:fe0e:b01c/128   [::]                       Un   0   7     =
0 eno1
ff00::/8                       [::]                       U    256 5     =
0 eno1
[::]/0                         [::]                       !n   -1  1     =
0 lo
root@mars:/etc/postfix#

N=