IPv6 missing from the fiber connection

[jensk]

Hi all,

I got a fiber connection via TNG (Germany) and IPv4 works great.
But IPv6 does not work.

When I look at the logfile I see this messages:

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<13>1 2026-05-07T22:25:12+02:00 OPNsense.internal dhcp6c 79084 - [meta sequenceId="381"] dhcp6c_script: REQUEST on pppoe1 connected to server
<13>1 2026-05-07T22:25:12+02:00 OPNsense.internal dhcp6c 84865 - [meta sequenceId="382"] dhcp6c_script: REQUEST on pppoe1 prefix now 2a00:ffff:ffff:8000::/56

When I manually add a ipv6 address in the sub net, it is working. But that is of course not doable all the time.

Code Select Expand

# ifconfig pppoe1 inet6 2a00:ffff:ffff:8000::1 prefixlen 64 alias
the "request prefix only" is disable. (I also tried it enable, same problem).

 Does anyone has an idea what I did wrong?

I setup a new OpnSense 26.1.7_3-amd64 host, so it is a fresh install

I read: https://docs.opnsense.org/manual/how-tos/ipv6_dsl.html.

CU
Jens

[Patrick M. Hausen]

What does TNG's documentation or their tech support say?

[jensk]

They support only certain fritz boxes. I contacted them for more information, but no infos yet.
I just found someone who got it working, so I know is is possible. . I will ask there as well.

[meyergru]

In your linked thread, someone says that TNG by default does not hand out IPv6, but you can request it to be enabled.

[jensk]

Yes, but my logs show that I get a IPv6 subnet so it is enabled.

[meyergru]

Then I do not get why using "request prefix only" with 56 bits like shown here would not work. I know of ISPs not liking requests without "request prefix only" and then handing out no address at all - mine, for example does that.

[jensk]

Hi,
thanks for the Link. I tried again and found the stupid error.
I forgot the set:

Optional prefix ID    
Optional interface ID

Now it is working. Thanks for the help!