Use safely: Follow these steps only for a router or network you own or are authorised to manage. Never send Router Portal a router password, Wi-Fi key, MAC address, serial number or private screenshot.
Evidence and scopeSOURCE-BACKED · CHECK DATE
Sources2 official references
ScopeModel/OS/network dependent
CredentialsNever universal
ReviewRecheck after UI changes
Quick answer: A router may have IPv6 capability but still lack a delegated prefix for its LAN. The WAN status and ISP handoff determine what the router can advertise internally.
What this page covers
Use the router’s IPv6 status and provider documentation rather than guessing a prefix size or manual address.
Step-by-step workflow
- Record the IPv6 WAN status and delegation error privately.
- Check whether the ISP requires DHCPv6-PD, PPPoE or another handoff.
- Confirm the LAN has a delegated prefix before changing RA settings.
- Ask the provider if the service supports third-party router delegation.
Decision table
| Check | What it tells you | Safe next action |
|---|---|---|
| No delegated prefix | LAN cannot build its normal global subnet | Check WAN handoff/provider |
| WAN IPv6 only | LAN advertisement may be incomplete | Review router IPv6 mode |
| Prefix changes after reboot | Lease or provider policy may vary | Record dates and source details |
Limits and verification
Exact prefix sizes and WAN values are provider-specific and should never be invented from a generic IPv6 guide.
Official sources
- IETF RFC 8415 — DHCP for IPv6 (DHCPv6 behavior)
- Google Fiber — Use your own router (fiber handoff considerations)
Related Router Portal guides
Router login troubleshooting · Router security guide
Editorial note: This pilot page is written for one distinct question. Firmware, operating-system menus, ISP policies and regional radio rules can change, so confirm the source and exact device before applying a setting.