RT-BE88U: IPv6 routing fails for LAN clients

[jzchen]

Thanks. Mine is Spectrum in Calif. running coax to a modem (modem only) then to the Asus router (Cat6) with 1 Gbps down service. All devices/computers are on wifi serving by Asus router.

I'm pretty sure I tried the combination of settings that I shared, and eventually factory reset, then just simply enabled IPv6 to Native...

EDIT: This is my OnePlus Open result, I believe same as wired...

 

[jzchen]

AiProtection has been on...

 

[marsman]

Thanks. I think my problem is that my local computers connected to the router didn't get a public ipv6 address? The router got a public ipv6 address (in addition to local ipv6 address) and is fine pinging ipv6 hosts on Internet from the router. My computer only got a local ipv6 address.

 

[marsman]

I also just connected my computer directly to the LAN port on the router and still not working so it wasn't with wifi.

Pinging from the router to ipv6 host worked, but pinging from local computer didn't:

PING ipv6.google.com (2607:f8b0:4007:80c::200e): 56 data bytes
64 bytes from 2607:f8b0:4007:80c::200e: seq=0 ttl=117 time=11.828 ms
64 bytes from 2607:f8b0:4007:80c::200e: seq=1 ttl=117 time=14.273 ms
64 bytes from 2607:f8b0:4007:80c::200e: seq=2 ttl=117 time=13.503 ms
64 bytes from 2607:f8b0:4007:80c::200e: seq=3 ttl=117 time=13.906 ms
64 bytes from 2607:f8b0:4007:80c::200e: seq=4 ttl=117 time=11.214 ms

--- ipv6.google.com ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 11.214/12.944/14.273 ms

 

[jzchen]

I just checked and my phone has 3 IPv6 addresses:
fe80::...
2600:xxxx:xxxx:xxxx:yyyy:yyyy:yyyy:yyyy
2600:xxxx:xxxx:xxxx:zzzz:zzzz:zzzz:zzzz

xxxx part is exactly the same...

Seems like Spectrum is also dual stack and should be the same. Please check if the modem model is IPv6 friendly, (minimum DOCSIS 3.0 from my search).

 

[jzchen]

This is from Windows 11 PC/desktop 25H2. The DNS addresses (there are two, is strangely the exact same, also they are the IPv6 address of the router:

 

[jzchen]

From my PC checking if the DNS works...

Microsoft Windows [Version 10.0.26200.8037]
(c) Microsoft Corporation. All rights reserved.

C:\Users\jzche>ping ipv6.google.com

Pinging ipv6.l.google.com [2607:f8b0:4023:1002::8b] with 32 bytes of data:
Reply from 2607:f8b0:4023:1002::8b: time=32ms
Reply from 2607:f8b0:4023:1002::8b: time=32ms
Reply from 2607:f8b0:4023:1002::8b: time=32ms
Reply from 2607:f8b0:4023:1002::8b: time=33ms

Ping statistics for 2607:f8b0:4023:1002::8b:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 32ms, Maximum = 33ms, Average = 32ms

C:\Users\jzche>

 

[jzchen]

Just in case it's different part of the WAN settings, (as I can not figure out how to take a scrolling screenshot):

 

[marsman]

I just checked and my phone has 3 IPv6 addresses:
fe80::...
2600:xxxx:xxxx:xxxx:yyyy:yyyy:yyyy:yyyy
2600:xxxx:xxxx:xxxx:zzzz:zzzz:zzzz:zzzz

xxxx part is exactly the same...

Seems like Spectrum is also dual stack and should be the same. Please check if the modem model is IPv6 friendly, (minimum DOCSIS 3.0 from my search).

My phone only got a FE80:xxx which is local ipv6. My router log showed the router got a public ipv6 (2600:xx) and a local ipv6, also the wifi guest network got its own public/local ipv6. For some reason, my phone and computer did not get their own public ipv6 addr connected to this network.

 

[jzchen]

My phone only got a FE80:xxx which is local ipv6. My router log showed the router got a public ipv6 (2600:xx) and a local ipv6, also the wifi guest network got its own public/local ipv6. For some reason, my phone and computer did not get their own public ipv6 addr connected to this network.

Maybe reboot the computer while connected to the LAN port. Check again what the DNS address is. It should be the router IPv6 address if it is like AT&T service, even if it doesn't make sense to...

Ping the actual Google IPv6 address. Does it go through?

EDIT- After connect it directly to the modem and try pinging the actual IPv6 address and see if it goes through...

 

[marsman]

Looking at the populated ipv6 fields on the router, I saw a LAN public ipv6 address of '2600' and a LAN prefix len of '64'. Is the /64 the problem? That field cannot be changed.

 

[marsman]

Maybe reboot the computer while connected to the LAN port. Check again what the DNS address is. It should be the router IPv6 address if it is like AT&T service, even if it doesn't make sense to...

Ping the actual Google IPv6 address. Does it go through?

I could ping from the router to ipv6.google.com just fine, but not from the computer as it said unreacheable.

 

[jzchen]

Looking at the populated ipv6 fields on the router, I saw a LAN public ipv6 address of '2600' and a LAN prefix len of '64'. Is the /64 the problem? That field cannot be changed.

As far as I know this just means your network is assigned the first 64 bits 2600:xxxx:xxxx:xxxx <- this part should be the exact same. Even if you choose Stateful then it will give you a default range of 1000 so 2600:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:yyyy where the yyyy is 1000 values just like for IPv4 2-254.

 

[jzchen]

I could ping from the router to ipv6.google.com just fine, but not from the computer as it said unreacheable.

Right, but is that because you are not getting DNS service, or because the router is not allowing IPv6 traffic through? If you ping the actual IP address and it works then DNS problem. If it doesn't then traffic is not getting through...

 

[jzchen]

Then if you connect the computer directly to the modem. If everything is fine then you just narrowed it down to the router...

 

[marsman]

I'm connecting directly to the LAN port, no luck.
BTW, what's your prefix len that was assigned? Mine is /64 and that may be the problem there.

 

[jzchen]

I'm connecting directly to the LAN port, no luck.
BTW, what's your prefix len that was assigned? Mine is /64 and that may be the problem there.

Same, 64. Assigned by ISP. Did you get to try computer directly to modem? To rule out the computer?