IPv6 on Deutsche Telekom very unstable, PPPoE reload dyfunctional since 23.1

[TheDJ]

Anyone tried the Zyxel modem with official Telekom firmware?

Not sure, what Zyxel modem you are referring to specifically. However, I'm running the Zyxel DX3301-T0 (https://geizhals.de/zyxel-dx3301-t0-dx3301-t0-de01v1f-a2753549.html) in bridge mode with Supervectoring and as I said, I experience the v6 prefix dropouts (the Github issue is mine).

That after a reconnect the IPv6 is not established is indeed in my opinion an OPNsense issue. And I feel it is a timing issue. because when I manually force a reload of the PPPoE connection then IPv6 works perfectly.
The only thing that would be needed in my opinion, is some task that monitors if IPv6 addresses are assigned after PPPoE is up and if not bounce the connection again and re-establish.
I wonder if that can be done via monit?

This was also a suggestion I made in the issue as a temporary workaround to at least make it stable. However, I'm not sure if DTAG has a rate limiting or if that would break other parts as well. Also, I did not receive any comment on the idea by the maintainers.

[sbellon]

It would probably be beneficial to use Interfaces: Settings: Prevent release. Usually the infamous "Zwangstrennung" disconnects the line, but not the leases...

It looks like *this* makes a big difference indeed.

The "Request only IPv6 prefix" does change the behaviour regarding whether the WAN gets its own IPv6 address or not (and actually works like advertised), however it has no influence on the dhcpd6 sometimes not running after a forced connect.

However ticking "Prevent release" makes a difference. Since I did that ~10 days ago, I have not yet run into that situation again. Let's keep it that way. :-)