u/wulingyun

ENVIRONMENT
- Parent node: MX5300v1, firmware [1.1.12.210066]
- Child node 1: MX5300v1, firmware [1.1.12.210066]
- Child node 2: MX4200, firmware [1.0.13.216903]
- Backhaul: Wireless
- Upstream router: Xiaomi BE6500 Pro
- Connection: Ethernet, upstream router LAN port to Velop parent WAN port


PROBLEM
In Bridge Mode, IPv6 does not work on child nodes. The client shows a correct IPv6 address and gateway, but cannot access any IPv6 website. IPv4 works fine.


HOW TO REPRODUCE
1. Set up the Velop system in Bridge Mode.
2. Connect a client (iOS or macOS) to a child node's Wi-Fi.
3. Disconnect Wi-Fi and reconnect.
4. The client shows a valid IPv6 address and correct gateway, but IPv6 internet access does not work (web pages fail to load).
5. IPv4 works normally at the same time.
6. Run "ping6 <upstream gateway link-local address>" from the client. The ping succeeds.
7. Immediately after the ping6, IPv6 internet access is restored.
8. Disconnect and reconnect Wi-Fi — the problem returns. Repeat step 6 to fix it again.
This cycle is 100% reproducible.


ADDITIONAL OBSERVATIONS
- Parent node is not affected. Clients connected to the parent node's Wi-Fi have no IPv6 issues in any mode.
- The problem only occurs in Bridge Mode. When the Velop is set to NAT mode with IPv6 set to "Passthrough," IPv6 works correctly on all nodes, including child nodes.
- Bridge Mode does not offer a "Passthrough" option for IPv6 — it is locked to "Auto." This means there is no workaround within Bridge Mode.


COMPARISON
- Bridge Mode, IPv6 Auto (forced, no other option) --> IPv6 on child nodes: NOT WORKING
- NAT (DHCP) Mode, IPv6 Passthrough                --> IPv6 on child nodes: Working


CURRENT WORKAROUND
Using NAT mode with IPv6 Passthrough. This resolves the IPv6 issue but introduces double NAT for IPv4 and puts clients on a separate subnet.


REQUEST
Could the engineering team investigate IPv6 handling in Bridge Mode on child nodes? The fact that the same hardware works correctly in NAT + Passthrough mode suggests this is a firmware issue, not a hardware limitation.


Alternatively, adding an IPv6 "Passthrough" option to Bridge Mode would give users an immediate workaround.