Quote from: Othvez on April 15, 2026, 04:29:55 PMThis sounds like stale RA lifetimes rather than dnsmasq itself, clients keep old prefixes until they expire. Have you checked if your RA settings properly deprecate old prefixes or tried lowering valid/preferred lifetimes?
Dnsmasq should deprecate old prefixes automatically if I use it for the RAs, when set up new, or? But it doesn't. All machines accumulate and try to use these prefixes until their lifetime is up (that was 84600 secs (unconfigured). I set these down to 7200 seconds, but these have still to time out the full lifetime until they are not (erronoeusly) used anymore.
And if I restart my OpnSense Router with dnsmasq set up three times, I get a new set of three "valid" IPv6 addresses on each machine, although the prefixes are deprecated, which are all tried to be used despite being deprecated. I haven't tested but it's also possible that these deprecated addresses are renewed once the lifetime is up despite being deprecated. I'm not sure what's wrong with dnsmasq but it doesn't deprecate old prefixes, it seems. Not sure what settings are wrong.
In the meantime I've gone back to the old, original RA service in the router by completely rolling back my settings from backup. So now I'm using the original RA service with th the old ISC DHCP server and the problems are gone for now. But I really want to use dnsmasq for its advantages in future (together with unbound), because it completely resolves also dynamic IPv6 addresses (DNS) for dhcp(v6), dns and RAs. But if it stays this way, there's no way for me to use dnsmasq.
I would be really thankful, if someone could point out which settings I have to apply to correctly deprecates old prefixes and what could be wrong.
Thank you,
fab
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