Bug#984707: systemd-networkd: DHCP-assigned IPv6 address lost after router restart, backport of bd7d6cec

[Tiziano Müller]

Hi Michael,

ok, I just tried with the patch (I hope so at least, I followed one of 
the tutorials, using `debuild -us -uc -i -I -b` to build the package 
after I patched the source and added the patch to `debian/control`, then 
installed with `sudo debi`).
Unfortunately it doesn't seem to solve the issue :(

After the last stable release it seems that some dependencies were 
updated which allowed me to finally use systemd-247 from the 
buster-backports, but that one also does not solve the issue.

So, it seems I have to dig deeper and/or wait for systemd-248 (or roll a 
custom package) since there are more IPv6 fixes flying in:
https://github.com/systemd/systemd/commit/12f7469bbe0142d7f360a29ca2b407ce7f5ff096

Since this happens during router restart (rather than just link-loss) my 
guess is that systemd switches to using SLAAC as soon as the link is up 
again (but before the DHCPv6 server on the router is ready) and then 
ignores the IP it would get from DHCPv6. But then I guess I have to do 
more serious reading into IPv6 to fully understand this.

If you want you can close this issue since at the moment it is unclear 
whether or not the issue is fixed at upstream or not.

Best regards,
Tiziano

On 3/18/21 9:17 PM, Michael Biebl wrote:
> Am 18.03.21 um 12:48 schrieb Michael Biebl:
>> On Tue, 16 Mar 2021 16:36:24 +0100 =?UTF-8?Q?Tiziano_M=c3=bcller?=
>> <tm at dev-zero.ch> wrote:
>>> Hi Michael,
>>>
>>> thank you very much for the reminder, I will try to build the package
>>> with the patch as fast as I can and see whether I can verify that it
>>> fixes the issue.
>>>
>>
>> Just a heads up, that I will prepare the package for 10.9 this Thursday
>> evening.
>>
> 
> This has just happened, see #985472
> 
> So let's do that in 10.10 then (which should happen in 2-3 months). 
> Would be great if you can report back with your findings by then.
> 
> Regards,
> Michael
> 
> 
>