[BUG] IPV6 DHCP-PD does not work with >64 prefixes on ASUSWRT

[ankhazam]

Hello @ASUS_ASUSWRT,
mentioned bug is present in all ASUSWRT firmwares in both 378 and 380 branches up to 380_2695.

It hase been already mentioned here http://www.snbforums.com/threads/of...on-3-0-0-4-378-9177.27372/page-13#post-211944 though to raise it importance I wished to make a separate topic related to it. As mentioned in those posts user @charlie2alpha has confirmed it for his /56 prefix as I have for my /60 prefix.

Situation:
- ISP with IPV6 over DHCP-PD
- IPV6 native setting (I assume it won't matter if it is PPP* or Ethernet interface
- the ISP announces prefix delegation greater than 64 and the router fails to properly resolve routing.

My case example:

Thanks RMerlin and charlie2alpha for your responses. Well my ISP states that the CPE he provides -- a Mikrotik Routerboard works good with this his configuration by resolving one of the 16 /64 networks available within the /60 prefix, eg ::2/64 .

The thing is that ASUSWRT tries to bind itself on the whole provided /60 prefix and therefore fails to resolve the ipv6 gateway.

This is what happens:

IPv6 Connection Type: Native with DHCP-PD
WAN IPv6 Address: 2a06:[someIPV6part]::1
WAN IPv6 Gateway:
LAN IPv6 Address: 2a06:[someIPV6part]::1/60
LAN IPv6 Link-Local Address: fe80::[someotherIPV6part]:a890/64
DHCP-PD: Enabled
LAN IPv6 Prefix: 2a06:[someIPV6part]::/60
DNS Address: 2001:4860:4860::8844 2001:4860:4860::8888

and the stateful hosts are

IPv6 LAN Devices List
-------------------------------------------------------------------
Hostname MAC Address IPv6 Address
Ha* [MAC1] 2a06:[someIPV6part]::66c5
An* [MAC2] 2a06:[someIPV6part]::1b16

The result:
- router is happy to confirm that it is configure with native IPV6
- some settings are passed to client computers
- the clients have no IPV6 internet access whatsoever

Sidenote:
- IPV6 confirmed to work with 6t04 setting though that's a dirty workaround when I can use native ipv6

I look forward to hearing from you,
Ank

 

[ankhazam]

Hello there, the issue still hasn't been fixed... any ideas when can we expect a fix?

 

[KevTech]

You should contact: Asus network support

 

[ankhazam]

I believe there are a dozen of SNB members related to ASUS who are aware of the issue The question is why is there work done on this particular bug.

 

[Deleted member 22229]

I have zero issues with native IPv6 using Asus routers or is there something i am missing here ?

 

[sfx2000]

I have zero issues with native IPv6 using Asus routers or is there something i am missing here ?

There's a number of different ways to handle ipv6, and OP's one is a bit problematic - nothing wrong with what the ISP is doing, but each ISP seems to be doing something different...

 

[Deleted member 22229]

It is unfortunate IPv6 was suppose to be the next major change to surfing the web. Instead it has not taken hold and has been a source of constant issues for many people.

 

[sfx2000]

Instead it has not taken hold and has been a source of constant issues for many people.

And vendors... which are taking the heat for that mess...

 

[ankhazam]

I have zero issues with native IPv6 using Asus routers or is there something i am missing here ?

Does your ISP provide DHCP-PD with greater than /64 prefixes? e.g. /60 prefix?

 

[Deleted member 22229]

Native DHCP prefix length 64

 

[ankhazam]

yup, and the issue is when you are assigned a network bigger than 64... In my case 60

 

[ankhazam]

Hi, anyone knows if this bug is fixed in the 3.0.0.4_380.3459 release?

 

[RMerlin]

Can you give a try to the latest alpha build of my firmware?

http://www.snbforums.com/threads/alpha-preview-builds-for-asuswrt-merlin-380-60.32978/unread

I fixed a bug related to prefix delegation, wondering if that would fix your issue.

 

[ankhazam]

Can I later get back to my nicely (besides the ivp6 bug) working 380_2695?

 

[RMerlin]

Can I later get back to my nicely (besides the ivp6 bug) working 380_2695?

Yes, if you use Firmware Recovery mode.

 

[ankhazam]

or jump to stable firmware from Asus without any issues simply from the UI?
ASUS RT-AC87U Firmware version 3.0.0.4_380.3459

 

[RMerlin]

or jump to stable firmware from Asus without any issues simply from the UI?
ASUS RT-AC87U Firmware version 3.0.0.4_380.3459

380.60 is compatible with the new firmware format, so yes, you will be able to directly upgrade to the newest 380_3xxxx releases, but the same limitations will still apply once on 380_3459 - reverting back will require using firmware recovery mode.

 

[ankhazam]

ok, thanks for the info. Will try to give your alpha a spin on the weekend then.

 

[sfx2000]

I fixed a bug related to prefix delegation, wondering if that would fix your issue.

John has a couple of fixes in his fork, did he push them back over to your repo?

 

[john9527]

John has a couple of fixes in his fork, did he push them back over to your repo?

Back on my fork, a lot of the places where it used prefix length were hard coded to 64. I've been fixing them as I find them, but as of now, haven't changed the gui to allow the change. Note also, that the fork uses a different IPv6 stack from the later Merlin builds. This change is all Merlin AFAIK.