RT-AC56U IPv6 No Connection on Ethernet

When I enable IPv6, seem like router won't assign an IP address on the Ethernet ports, wireless devices still work fine.

Am curious about what version of Merlin you installed and if you find it improves how the AC56U functions. I've had mine for about 3 weeks now running the latest version of Asus firmware and am trying to justify changing it when it seems to work fine. From this thread it appears you're having problems.. Did you get them fixed?

1) your ISP supports IPv6?
2) your modem supports IPv6?

Yes, tried using Charter's 6rd and also 6to4, both no IP assigned on Ethernet but wireless devices are fine. I tried doing the winsock reset and everything.

I have ATT uverse.

My ATT gateway router was enabled for IPv6 a month ago.

I had to buy a new ipv6 capable router to replace an older linksys that didn't support ipv6.

I go the Asus RT-AC56U

The AC56U has the latest firmware loaded according to Asus support page.

I have configured the ASUS RT-AC56U for IPv6 -
Connection Type = NATIVE,
DHCP-PD = ENABLED,
Auto-Configuring = STATELESS,
Connect to DNS Server Automatically = ENABLED,
Enable Router Advertisement = ENABLED.

I have enabled SSH access into the ASUS RT-AC56U and after logging into it directly (using ssh)

I executed "ifconf" and it DOES SHOW the Eth0 interface DOES get a good IPv6 address !

In the AC56U the... Eth0... is the WAN port that is on the same LAN as my ATT Router (internal net 192.168.1.x)

However the ASUS RT-AC56U ifconfig shows that the NONE of the other interfaces get a good IPv6 address -or- connectivity via IPv6.

On he AC56U (BR0 .. the WiFi port) and the other ETH1, ETH2, ETH3 ports are the ethernet ports on the back of the router.

All of those ports including the wifi just get a default Link-Local IPv6 which means nothing attached to them can talk IPv6 to the internet.

From the ssh session into the ASUS RT-AC56U I can "ping6 ipv6.google.com" successfully! So the AC56U itself got configured for IPv6
correctly from the ATT gateway.

However, from none of the laptops, connected to the ASUS RT-AC56U wifi .. can I "ping6 ipv6.google.com" ... they all fail/network not found.

SO... this ASUS RT-AC56U router itself has IPv6 it was given by the ATT uverse router but NOTHING behind the ASUS...
ie my pc's & laptops connected via ethernet or wifi can get IPv6 connection to the Internet??

I'm not sure what to try next but it seems to me that the ASUS RT-AC56U even with the latest firmware must have some bug or perhaps I need to do a Static IPv6 configuration... maybe the NATIVE Connection Type is broken ?

Brian

bmullan said:

I'm not sure what to try next but it seems to me that the ASUS RT-AC56U even with the latest firmware must have some bug or perhaps I need to do a Static IPv6 configuration... maybe the NATIVE Connection Type is broken ?
Brian

Click to expand...

Native IPv6 works perfect on my AC56U with the latest Asuswrt-Merlin. In the IPv6 tab at System log you can see which devices have a IPv6 adress.
http://192.168.1.1/Main_IPV6Status_Content.asp

easyriider said:

Native IPv6 works perfect on my AC56U with the latest Asuswrt-Merlin. In the IPv6 tab at System log you can see which devices have a IPv6 adress.
http://192.168.1.1/Main_IPV6Status_Content.asp

Click to expand...

thanks... I just got this Asus RT-AC56U

I just flashed & tried the asuswrt-merlin and there's no change at least for me & my setup.

My rt-ac56u is connected by ethernet to my att uverse modem/router/wifi box.

My rt-ac56u though is not showing any IPv6 devices from the gui except my WAN port connection to the ATT router

Again, using ssh to login to the rt-ac56u... I can see that the Eth0 interface does get a valid IPv6 . Note: in the ssh session at the CLI ifconfig Eth0 being the same as looking at the GUI's WAN interface.

Brian

Maybe your modem or provider hasn't activated prefix delegation, that is necessary to give the router its own IPv6 prefix. Without an own prefix the router cannot give other devices an address. If that's the case you can try a static setup, but I have no experience with that.

easyriider said:

Maybe your modem or provider hasn't activated prefix delegation, that is necessary to give the router its own IPv6 prefix. Without an own prefix the router cannot give other devices an address. If that's the case you can try a static setup, but I have no experience with that.

Click to expand...

As my original post said... any devices (laptops, PCs) that connect to the ATT uverse's modem/router/wifi get both ipv6 & ipv4 addresses ok and I can ping6 just fine.

My problem is the asus rt-ac56u when setup for Native ipv6 does get an ipv6 address from the att uverse modem/router/wifi (both routers are on the same ethernet).

But the Asus rt-ac56u only gets an IPv6 on its own WAN port (the lan link to the ATT uverse router).

The Asus wifi ports and the 4 physical LAN ports on the rear of the Asus all fail to get configured for IPv6.

ATT gave me a /64. Not sure why the ipv6 config of LAN and Wifi side of the asus is not being configured correctly. I've quite a few other web posts so far with what sounds like more or less the same problem as me. One common approach was swapping out the pace uverse for a motorola modem that perhaps supports ipv6 more?

bmullan said:

As my original post said... any devices (laptops, PCs) that connect to the ATT uverse's modem/router/wifi get both ipv6 & ipv4 addresses ok and I can ping6 just fine.

My problem is the asus rt-ac56u when setup for Native ipv6 does get an ipv6 address from the att uverse modem/router/wifi (both routers are on the same ethernet).

But the Asus rt-ac56u only gets an IPv6 on its own WAN port (the lan link to the ATT uverse router).

The Asus wifi ports and the 4 physical LAN ports on the rear of the Asus all fail to get configured for IPv6.

ATT gave me a /64. Not sure why the ipv6 config of LAN and Wifi side of the asus is not being configured correctly. I've quite a few other web posts so far with what sounds like more or less the same problem as me. One common approach was swapping out the pace uverse for a motorola modem that perhaps supports ipv6 more?

Click to expand...

I just reconfigured the asus rt-ac56u to Access Point mode instead of Router.. as a work around for me. Since my Asus & ATT routers were both on the same ethernet this would work for me because the Asus rt-ac56u documentation says the Access Point mode must be a lan connection to the upstream router.

Also, this puts the Asus more into a bridge type modem so IPv6 DHCP requests coming from client devices (laptops, pc, roku etc) all now get a good IPv6 address when they boot. This will work ok until I can talk to ATT.

This thread has the best technical description I've read about the overall problem: http://superuser.com/questions/716579/no-ipv6-with-asus-rt-n56u

bmullan said:

ATT gave me a /64. Not sure why the ipv6 config of LAN and Wifi side of the asus is not being configured correctly. I've quite a few other web posts so far with what sounds like more or less the same problem as me. One common approach was swapping out the pace uverse for a motorola modem that perhaps supports ipv6 more?

Click to expand...

If they give you a /64 prefix the modem cannot delegate prefixes to a router, a /56 prefix is quite normal so the modem can delegate 255 other prefixes to requesting routers.

easyriider said:

If they give you a /64 prefix the modem cannot delegate prefixes to a router, a /56 prefix is quite normal so the modem can delegate 255 other prefixes to requesting routers.

Click to expand...

Incorrect. WRONG WRONG WRONG. I have a /64 from TWC on my RT-AC87U. the modem is in bridge mode so it doesn't even pick up an iov4 or 6.. It acts like an old fashioned frame relay modem. ALL the routers requests are sent DIRECTLY to your ISP. ANY asus router (from the 56u and up) with proper firmware can delegate ANY /PREFIX.

/64 gives out IPs fine BUT YOU MUST TURN ON DCHPV6 even in stateless mode and even with dchp-pd. In my case I don't use any dchp or dns on my router. My connection is so fast it overloads it even it CT+AF mode. It takes newer 400-600 asudnrouters to fully support 1Gb/sec connection. I'm at 350x25 and even bypassing the cpu using hw acceleration, the unit heats up and crashes 1-2X/day. IPv6 doesn't need Nat... So it doesn't need to use the cpu for or hw accell.. The more sites that use IPv6, the cooler my unit runs over time. I'm probably overdue for a FW update too. I'd go 100% IPv6 but then I couldn't connect to 1/2 the websites out there.

 Typical IPv6 prefix assignments:
– Service provider (LIR): /32, 2^32/64 subnets.
– Large end user: /48, 65535/64 subnets - absurd for the home or small-mend business
– Medium end user: /56, 256/64 subnets - not needed for consumers.
– Small/ Home/ SOHO: /64 or /60 1 or 16 /64 subnets

The asus router can use all of those, but /64 is best. 1, /64 subnet. /56 is far more complex 256 /64 subnets and the asus can only do ONE. you'd need other servers and or routers for more subnets. But it still can do ONE /56 or ONE /48, /32, ETC


Good news for iPad / iPhone / OS X users... ANY app put on the App Store must fully support IPv6 and if it's a client server app, and servers are IPv4, it's up to them to do the 6 to 4 conversion. Apple gave existing apps until 2017 to b fully IPv6 compatible. Ios9 defaults to IPv6, if available then falls back to IPv4. Same with OS X and windows. Microsoft issued a similar mandate. Unsure about android.

Why ppl think a /64 won't work is BEYOND ME. RFC4294 suggestS ALL CONSUMER PREFIXES BE /64 for now http://www.txv6tf.org/wp-content/uploads/2012/09/Doyle-IPv6-Address-Design.pdf
It's a few yrs old but very valid. BUT AS LONG AS U GET A PREFIX WITH ANY /XX, the asus router WILL DELEGATE. AND UT STATELESS IT DIESNT HAVE TO. router advertises the prefix and /xx and clients take it from there. If no stateless dhcpv6 , clients assume the gateway and dns are one in the same. '

If unwanted more control , use state full to list a range within the prefix and specific Dns servers to pass to clients

You can also go stateless with no dvhpv6 and no router advertisement. You get the prefix off your router and set up, for example a stateless dchpv6 server with router advertisement on a win 2008 or 2012 server. This is far more complex. The win server will tell clients the stateless info they need to auto configure but will give them other settings, if configured, name servers (dns), gateway, and a bunch of other options the asud can't do. Or u can go state full assign a scope with dchpv6 reservations ...but if your ISPs changes your prefix.. You have work to do.

My 64bit 2008r2 server runs under oracle virtual box on my PCs and only needs 1GB ram and 2 virtualized CPUs. I have 32GB so it's not missed. Even 16 would b fine.

IPv6 gives 2 to the 128th power addresses vs 4.3B IPv4 addresses
OR
340,000,000,000,000,000,000,000,000,000,000,000,000 IPV6 addresses or simply 340 undecillion IPv6s or ... 340 trillion septillion.... 340 million nonillion That's not running out. Even if we had 10billion people and each had 10 devices between home and work...that's 100B IP 6 needed. Even if each 10B used 1000 IPv6 addresses , that's 10 trillion IPv6 needed. Not counting isp routers , etc. 10 trillion is only 10,000,000,000,000 compared to a pool of 340,000,000,000,000,000,000,000,000,000,000,000,000. That wouldn't run out even 500 yrs. . MAYBE LONGER.

anyway the most COMMON IPv6 assigned by a native IPv6 connection is /64 with /56 coming in second. Your router should handle ANY PREFIX. I set mine to 2001::/128 and I got IPv6 addresses but non routable lol.

You can also do STATIC once u have a prefix as it RARELY will change. For /64, some devices are static and I just do prefix::1,2,3,4,5 etc. That gives them nice neat addresses. But in stateless mode a device gets many IPv6:
Primary
Temporary (can be 1-3)
Link local
In stateless mode, you can set primary to prefix::10 but

Some will go huh? STATIC without a full dchp, there will be conflicts. Nope. 1) u get too many IPs. 2) in IPv6 if a client is static , no other client will auto configure that IPv6

MAKE SURE TO TURN ON DCHPV6 FIREWALL! these are public ip addresses NOT hidden behind a NAT. ANY MAC or PC should have firewalls also.

The says stateless dvhpv6 just supplies the "other" info like DNS servers and gateway to clients. In state full mode it does more. But no reservations allowed. Use static on clients for that.

I'm running in
native mode
Dchp-pd
Router advertisement on

Operation Mode:Wireless router Firmware:378.55 (Merlin)

IPv6

Configure the IPv6 Internet setting of RT-AC87U.
Connection type Native
DHCP-PD Enable
IPv6 LAN Setting
LAN IPv6 Address
2606:a000:121d:405f::1
LAN Prefix Length
64
LAN IPv6 Prefix
2606:a000:121d:405f::
Auto Configuration Stateless
Lease time 86400
IPv6 DNS Setting

(.....405f::2 is my windows 2008 R2 server. It does dchpv4, dnsv4&6, it also has a stateless dhcpv6 server that lets stateless clients get other and more info than the router could ever give. It also registers clients with the Dns server for forward and reverse lookups) but what I do is OPTIONAL.

Connect to DNS Server automatically Disable (I do not want to use my ISPs dns)
IPv6 DNS Server 1
IPv6 DNS Server 2
IPv6 DNS Server 3
... 2606:a000:121d:405f::2, 2001:4860:4860::8888, 2001:4860:4860::8844 (this puts the router in dons forward mode. And dons queries sent to it go to my server. If that fails, Google. But this is redundant as the "other" setting flag of a stateless dhcpv6 server assigns then to clients. It's just here in case my dns goes down)

Auto Configuration Setting
Enable Router Advertisement
Enable DHCPv6 Server


Lastly, you can have the router do only IPv6 and have a separate dchpv4/dnsv4 in your house/business. And most professional dns4 will do 6 also

easyriider said:

If they give you a /64 prefix the modem cannot delegate prefixes to a router, a /56 prefix is quite normal so the modem can delegate 255 other prefixes to requesting routers.

Click to expand...

Umm the modem should NEVER BE DELEGATING ANYTHING TO A ROUTER! Never never never never. It should just be that a DUMMY MODEM BRIDGE. any ALL isp modems (cable, dsl, fibre

If u use your own vs the crappy modem, router, and or wifi device they give you..you tell them: wifi OFF, BRIDGE MODE ON. then the modem does NOTHING...except bridge cable communications to Ethernet. Then your router talks directly to the ISP. This is allowed because the cable modem is certified and authenticated.

The modem is still accessible at 192.168.100.1

SO NEVER USE 192.168.100 as you Pvt IPv4. Use 192.168.0.x or 192.168.1.x...192.168.xxx can be used too just avoid 100. And sometimes it's best to avoid 1. Some cable modems use xxx.xxx.1.1

WHEN U HTTP to 192.168.100.1 , it's not part of your network. So it's forwarded to the router to handle. Normally it'd go nowhere but the cable modem has it so u can connect. This is why, even in bridge mode, you let it keep a LAN address but different from yours. You can even assign it a Pvt. Ipv6

But NEVER let the cable modem, as some allow this, to get an IPv4 or 6 WAN address in bridge mode. In theory it should affect anything since it is bridged..but some are crappy and it causes issues.