Hey everyone,
I’ve been trying to get a UniFi setup working properly with OCN over NTT FLET’S (Hikari Mansion), and I’m kind of stuck at this point.
With the default NTT router (RT-500KI), everything works fine. It connects using PPPoE for IPv4 and IPoE for IPv6, and internet is stable.
When I switch to my UniFi UCG-Max (cloning the RT-500KI's MAC Address for authentication), PPPoE for IPv4 works without any issues. The problem starts when I try to use IPv6 or move to IPoE.
If I enable DHCPv6, the router doesn’t get any IPv6 address at all. If I switch to SLAAC, it does get a global IPv6 address on the WAN, but I still can’t actually reach anything over IPv6.
Then I tried switching to IPv4 over IPv6 (MAP-E) using the “OCN Virtual Connect” option in UniFi. When I do that, IPv4 becomes 192.0.0.2 and I lose internet completely.
The NTT router handles this hybrid setup fine as (probably with some NTT-specific behavior), but UniFi doesn’t deal well with it. When I use https://v6test.ocn.ne.jp with the RT-500KI router I get this result.
What I’m trying to achieve is a clean setup where the UniFi router is directly connected to the ONU, no double NAT, and ideally using IPoE / MAP-E instead of PPPoE. I know I can set a DMZ and put my UCG-Max there, but I'd like to avoid that.
Has anyone here actually gotten UniFi working properly with OCN Virtual Connect (MAP-E)? Or you basically need a Japanese router in front, or just switch ISP entirely?
Any experiences would really help. I feel like I’m close, but missing one key piece.
EDIT: I made it work!!!!
Got this working with a UniFi UCG-Max directly connected to the ONU (no NTT router).
ISP: OCN Hikari Mansion (NTT FLET’S)
WAN settings
- IPv4: IPv4 over IPv6 → MAP-E → OCN Virtual Connect
- IPv6: SLAAC → Single Network
LAN settings
- IPv6: Single Network
Important
- MSS Clamping: Custom → 1420
After reboot:
- IPv6 gets assigned
- MAP-E comes up (WAN IPv4 shows 192.0.0.2)
- It just works
by Last_Restaurant9177