Record the equipment change
Keep the old and new router roles, replacement time and whether the provider connection changed. A reused Wi-Fi name does not establish identical prefixes, routes or policy. The wired and wireless interfaces can also have different state.
Check whether ordinary external access fails or only one media resource does. A specific permission response is different from missing routing. Do not change a service password while the device cannot reach ordinary external destinations.
Identify automatic and manual state
Use the device and router's supported information views. IPv6 address configuration and lifetimes have defined mechanisms, and a device can hold more than one address. A local-link address alone does not establish a working global route.
Do not manually invent a new prefix or copy another device's complete address. If a static configuration was previously set, ask the network administrator whether it remains appropriate. Follow the provider's actual design rather than applying an IPv4-only recipe.
Compare on the intended network
Check a working client on the same actual link, with interface and network role understood. A guest segment or second router can legitimately advertise a different arrangement. Similar Wi-Fi names do not make the comparison identical.
An illustrative device can retain an old manual assignment while a newly configured client uses the new network successfully. That narrows a local configuration question. It does not prove the media account expired, the new router is defective or IPv6 must be disabled everywhere.
Verify a supported correction in order
After the administrator reconciles the configuration, check current address and route state, name resolution and ordinary external access. Then replay the original permitted item. Record the first remaining failure rather than continuing to edit network values blindly.
Keep address inventories and device identifiers private. A safe report can describe the old-versus-current prefix relationship and actual failed stage. The useful outcome is a coherent current network configuration with the original playback task tested separately, not a plausible-looking address copied into a field without a routing plan.
Related questions
Does an IPv6 address always stay valid when I move to another router?
No universal rule follows. Prefixes, lifetimes, interface state and the actual network design matter.
Sources and scope
Scope notes distinguish published documentation, supplied information and editorial methods. They do not report a hands-on service test.
