RM521F-GL not passing IPV6 traffic

I have IPPT enabled on the module, and the module is attached to my router via USB.
The router is configured for IPV6 passthrough, and devices on my network are receiving public IPV6 addresses.
Those devices are able to perform DNS resolution to public IPV6 addresses, but can’t ping those addresses.
The router itself is able to resolve IPV6 DNS resolutions and the router CAN ping those addresses.

For context, if I put the SIM back in the T-Mobile Home Internet modem that it came from, and connect that modem to the router, devices on the network receive public IPV6 addresses AND can ping public IPV6 addresses.

This limitation only happens when I’m using the RM521F-GL.

Is this a routing problem on the module itself?

Is it OpenWrt?
Could you provide any logs or screenshot?

The router is using Asuswrt (latest Merlin).
Fact is, I don’t think it’s the router, since IPV6 passthrough works just fine with this router if I use the modem that T-Mobile provides.

With the RM521F-GL and IPV6 passthrough, IPV6 addresses are assigned to my network devices and those devices have IPV6 DNS resolution, but the RM521F-GL simply isn’t passing IPV6 traffic to anything except the router.

My MPDN rule is using the MAC address FF:FF:FF:FF:FF:FF to perform passthrough to the router; could that somehow be causing the problem?
I would have thought that enabling passthrough to the router would have enabled passthrough for everything connected to the router, but I am hardly an expert at this.

I have the same issue with RM520N.
I do not think it is the router issue since I have tried on two different routers.
Were you able to figure it out?

Anyone else resolve this? Definitely seeing this too

I’m using the rm501f and my openwrt router gets an unfiltered ipv6 ip, but none of my devices on the network do. I think tmobile sees the router differently then their gateway and isn’t handing out ipv6 ips the same.

What do you mean?
Do you mean that the LAN cannot get the valid ipv6 address?
@dvsdan

Which usbnet mode do you use?
Any pictures about it?
Does the PC get the ipv6 address?

I’m using a T-Mobile internet SIM in an M.2 to RJ45 Sled with a RM520N-GL. I’m connecting via ethernet to a Wifi Router (Ubiquiti Dream Machine, UDM) for my house. When I enable SLAAC, it creates an IPv6 Proxy to provide IPv6 address and routing for the rest of my network. This only works with the T-Mobile provided gateways (all of them), not the Quectel card. The UDM does get an IPv6 address and can ping from there out, but I can’t get the network behind it to work with it. I can help debug the differences between the two devices, but not knowledgeable enough in IPv6 SLAAC/DHCPv6 to know what is wrong.

Additional info:
AT+QCFG=“usbnet”
+QCFG: “usbnet”,0

T-Mobile IPv6:
SLAAC based, no DHCPv6-PD available.

Running NAT mode on the RM520, but IPPT also doesn’t work in the exact same way. (i.e. device on ethernet gets IPv6, devices behind router get IPv6, but no routes are available to work through router.)

I think this is related to this thread:

I just tested it and it seems works fine.
How about if you do not enable the ippt?
Will the ethernet get global ipv6 address?

Sorry, but tested how? Did you actually test with a T-Mobile internet SIM?

I am able to get a working IPv6 address and routing on a device connected via ethernet, but any attempts at using IPv6 Proxy with a UDM fails where it works with the T-Mobile gateway.

I don’t have the T-Mobile simcard.
For ipv6 there is no such gateway. It is better to provide some logs.

Got it. Would love to provide logs. Are there instructions on how to do this and open a support case?

@Bean.Wang-Q , how can I provide logs? Please advise.