Messages

If the privacy-vpn-servers or your LTE-connection are overloaded, there is nothing OPNsense can do...

I don't see any mistake but there has to be one somewhere.

netsh interface ipv6 set privacy state=disabled store=persistent

Supi, das kam letztens woanders mal als Frage auf.

and I don't even have clients

Sure you do. Every PC, Phone whatever you have at home is a client.
Maybe it is a torrent client or a virus which leads to this blocked traffic...

danach habe ich in Win 11 die temporären IPv6 Adressen ... deaktiviert

Wie macht man das?

and I am sorry to have wasted your time.

Not only his. ;)

I am using DHCP on the WAN port.

Maybe you shouldn't. WAN should be PPPoE in your case.

usually it works out of the box

I have to correct myself, for a cable-modem it usually works out of the box but here the case is different, sry.

Are you using PPPoE or DHCP for your Internet? But at this point, I give up anyways.

Have I messed something else up?

I say yes because usually it works out of the box. So show all your LAN and Floating rules and maybe Outound-NAT if you changed something there.

And maybe, bring drag'n'drop for firewall rules. ;)

They say the IP is 192.168.0.1 in router mode and 192.168.100.1 in modem mode.

What is your WAN-Address in OPNsense?

My WAN IP is assigned by DHCP in OPNsense.

Then you don't have to do anything for reaching your modem. Show all your WAN-rules, maybe you are blocking private IPs.

What rule should I create to block access to the default LAN

Maybe a block-rule?

There is an option to "Renew DNS for WireGuard on stale connections" in System/Cron. Try it.