AT&T U-verse IPv6 Configuration in IOS

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Sat, 04/02/2016 - 10:34
Jun 14th, 2012
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AT&T's U-verse service is rolling out IPv6, at least initiallly, via 6rd tunneling. There is no official mention of this working anywhere on their IPv6 site (www.att.com/ipv6); it's been reverse engineered based on how some customers have been setup with a Motorola NVG510 modem rather than the more common 2Wire residential gateway. According to their public documentation, they will be rolling IPv6 to the 2Wire RGs via a firmware update through 2012; in the meantime, this method will get you some experience ahead of their rollout.


This works for me, today. It might stop working tomorrow if AT&T decides to take down their routers. I've left out all of the IPv4 configuration here, including security, which needs to be taken care of before you go down the road of putting your router out in the open.


The setup: I developed this on a Cisco 881W router with the router in DMZplus mode off of the 2Wire. FastEthernet4 is the WAN interface; Vlan1 is the inside of the network. I'm using CBAC (Context Based Access Control) for security - all inbound traffic not associated with an outbound connection, other than ICMP, is blocked.


IOS version 15.2(3)T, though any 15.2T release should work:


no ipv6 source-route

ipv6 general-prefix uverse 6rd Tunnel0

ipv6 unicast-routing

ipv6 cef

ipv6 inspect name V6-INSPECT tcp

ipv6 inspect name V6-INSPECT udp

ipv6 inspect name V6-INSPECT ftp

ipv6 inspect name V6-INSPECT icmp


ipv6 access-list v6filter

sequence 10 permit icmp any any

sequence 20 permit tcp any any established

sequence 30 deny ipv6 any any log


interface Tunnel0

no ip address

no ip redirects

ipv6 enable

ipv6 mtu 1450

ipv6 inspect V6-INSPECT out

ipv6 traffic-filter v6filter in

ipv6 virtual-reassembly in

tunnel source FastEthernet4

tunnel mode ipv6ip 6rd

tunnel 6rd prefix 2602:300::/28

tunnel 6rd br 12.83.49.81


interface Vlan1

description internal network

ipv6 address uverse ::/64 eui-64

ipv6 enable

ipv6 mtu 1450

ipv6 virtual-reassembly in


ipv6 route 2000::/3 Tunnel0 2602:300:C533:1510::


The ipv6 route points traffic at the same box as the tunnel - 12.83.49.81 is 2602:300:c533:1510::. This address is an anycast address that will resolve to the nearest 6rd gateway.


Once it's up and running we can verify with some show commands:


c881w#sh tunnel 6rd


Interface Tunnel0:

  Tunnel Source: <my external IP>

  6RD: Operational, V6 Prefix: 2602:300::/28

       V4 Prefix, Length: 0, Value: 0.0.0.0

       V4 Suffix, Length: 0, Value: 0.0.0.0

       Border Relay address: 12.83.49.81

  General Prefix: 2602:30X:XXXX:XXXX::/60 <X = my external IP in hex>



c881w#sh ipv6 route

IPv6 Routing Table - default - 4 entries

..

S   2000::/3 [1/0]

     via 2602:300:C533:1510::, Tunnel0

C   2602:30X:XXXX:XXXX::/64 [0/0]

     via Vlan1, directly connected

L   2602:30X:XXXX:XXXX:CA9C:1DFF:FEF2:5B0C/128 [0/0]

     via Vlan1, receive

L   FF00::/8 [0/0]

     via Null0, receive

Loading.
jwspade Wed, 09/04/2013 - 11:23
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Perfect. Works in 15.1T with Uverse in South Florida. Would not let me use Tunnel0 due to PIM, but changing to a different tunnel number worked fine. 

Henry Bonath Sat, 04/02/2016 - 10:34
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Can confirm this still works today, in Ohio. Used a 2811 on IOS 15.1(4)M2

Thanks for sharing!

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