tvjhh697a schrieb:
At the moment I have an issue with Telekom: from time to time, it is changing the ipv6 subnet assignet to me. This makes impossible to identify my devices by their ipv6 addresses.
Telekom enforces a PPPoE reconnect every 180 days, O2 however enforces a PPPoE reconnect every 24 hours (after the last connect). In both cases both IPv4 and IPv6 addresses/prefixes will change. The way around that is to use some sort of dynamic DNS service. And if you want to offer IPv6 services from your home network you need to configure your firewall accordingly. OpenWrt allows to mask out the non-inrerface-identifier portion of IPv6 addresses, so firewall rules can survive a prefix change.
tvjhh697a schrieb:
Does O2 also change a once assigned ipv6 subnet or does the assigned subnet stays for extended periods of time?
It changes every 24 hours… I base this on my recorded data (I run a few traceroutes every night and store the IPv6 prefix as part of my book keeping). If you need persistent addresses, maybe consider getting a business tarif, where IIRC persistent addresses are an option. Or consider dynamic DNS as a work-around.