IPv6 Configuration for Cisco 867VAE on Sky FTTC / VDSL

[speedyuk]

Hi, I've just purchased a Cisco 867VAE to give me more flexibility for my home network configuration to allow for a separate LAN segment for a Home Lab network

I've successfully configured the IPv4 for internet connectivity via 0.101

I'd like to also have IPv6 working for my normal internet access, to get me back to the same level of functionality as the Sky Hub.

I've upgraded the IOS to (C860VAE-ADVSECURITYK9-M), Version 15.4(3)M8 from July 2017 so I'm hoping that will provide the necessary support to be compatible with the Sky IPv6 deployment?

Please could someone share details of their IOS configuration for IPv6 using Sky FTTC / VDSL.

Many Thanks

[Shonk]

you realise that router is only rated for 12.8Mbps yes?
with some models being able to pull around 35Mbps

[speedyuk]

Hi Shonk, you seem to know a lot about this router. Are you able to assist with the IPv6 configuration for Sky VDSL / FTTC?

[skyeci]

my Opnsense box is set to dhcpv6, request prefix only, prefix delegation size 56, Directly send solicit - works a treat.

[speedyuk]

I've been doing some more work and I think I must be nearly there. Below are just the relevant IPv6 bits from my config. I can now see on my PC that I'm being allocated a Global IPv6 address on my adapter. I've removed some of the info. I'm wondering if it is just a access list / routing issue I'm missing now?

Connection-specific DNS Suffix . :
IPv6 Address. . . . . . . . . . . : 2a02:c7f:xxxx:xxxx:781c:xxxx:8408:a4d8
Temporary IPv6 Address. . . . . . : 2a02:c7f:xxxx:2d00:xxxx:xxx:8340:2bbe
Link-local IPv6 Address . . . . . : fe80::781c:3dcf:8408:a4d8%15
IPv4 Address. . . . . . . . . . . : 192.168.0.2
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : fe80::521c:bfff:fede:7de0%15

It was even showing 3 ipv6 DNS server entries at one point (not Global addresses)


Cisco867#show running-config
Building configuration...


Current configuration : 5873 bytes
!


ipv6 unicast-routing
ipv6 dhcp pool skyipv6dhcppool
prefix-delegation pool skyipv6pdpool
import dns-server
!
ipv6 cef
!
!


!
controller VDSL 0
no cdp run
!
!


!
interface ATM0
no ip address
shutdown
no atm ilmi-keepalive
cdp enable
!
interface Ethernet0
mac-address xxxxxxxxxxx
no ip address
ip nat outside
ip virtual-reassembly in
!
interface Ethernet0.101
encapsulation dot1Q 101
ipv6 address autoconfig default
ipv6 enable
ipv6 nd autoconfig default-route
ipv6 dhcp client pd skyipv6pdpool rapid-commit
ipv6 verify unicast reverse-path
no cdp enable
!


!
interface GigabitEthernet0
no ip address
!


!
interface Vlan1
description $ETH-SW-LAUNCH$$INTF-INFO-HWIC 4ESW$


ipv6 address skyipv6pdpool ::1/64
ipv6 enable
ipv6 nd other-config-flag
ipv6 dhcp server skyipv6dhcppool
!


!
!
ip nat inside source list 1 interface Ethernet0.101 overload
!
mac-address-table aging-time 10
!
access-list 1 permit 192.168.0.0 0.0.0.255
access-list 1 permit 10.0.0.0 0.0.0.255
access-list 23 permit 192.168.0.0 0.0.0.255
access-list 100 deny ip host 255.255.255.255 any
access-list 100 deny ip 127.0.0.0 0.255.255.255 any
access-list 100 permit ip any any
access-list 101 permit udp any eq bootps any eq bootpc
access-list 101 deny ip 10.10.10.0 0.0.0.255 any
access-list 101 permit icmp any any echo-reply
access-list 101 permit icmp any any time-exceeded
access-list 101 permit icmp any any unreachable
access-list 101 deny ip 10.0.0.0 0.255.255.255 any
access-list 101 deny ip 172.16.0.0 0.15.255.255 any
access-list 101 deny ip 192.168.0.0 0.0.255.255 any
access-list 101 deny ip 127.0.0.0 0.255.255.255 any
access-list 101 deny ip host 255.255.255.255 any
access-list 101 deny ip any any
!


end


Cisco867#

[skyeci]

look much like mine. I do specify open dns or Google servers for ipv6 dns rather than sky.

[speedyuk]

Thanks skyeci, I think my problem may be no IPv6 default gateway/route.

The output from show ipv6 route is

Cisco867#show ipv6 route
IPv6 Routing Table - default - 4 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, ND - ND Default, NDp - ND Prefix
DCE - Destination, NDr - Redirect, a - Application
S 2A02:xxxx:xxxx:2D00::/56 [1/0]
via Null0, directly connected
C 2A02:xxxx:xxxx:2D00::/64 [0/0]
via Vlan1, directly connected
L 2A02:xxxx:xxxx:2D00::1/128 [0/0]
via Vlan1, receive
L FF00::/8 [0/0]
via Null0, receive

I have no entry for ::/0

What mechanism do sky use to provide the default route?

Thanks

[marjohn56]

There is no WAN IP global address per say, Sky use link local to their router. On FreeBSD it's RTSOLD that does the job of advertising and setting the route, not sure how your Cisco does it.

[speedyuk]

Hi, I thought I'd let you know I have the IPv6 working now with my Cisco 867VAE. I was not going to be defeated. Most of my problem was due to doing what most normal IT engineers do and upgrade to the latest firmware. It seems Cisco have introduced either a bug or an incompatibility with the way Sky allocate the IPv6 default route / gateway. I found one other post on the net where someone else had the same issue and had to downgrade IOS to fix it. ( https://supportforums.cisco.com/t5/w...d/td-p/1733533 ).

It wasn't until I downgraded to Cisco IOS Software, C860 Software (C860VAE-ADVSECURITYK9-M), Version 15.3(3)M3, RELEASE SOFTWARE (fc1) that the ::0/ default route would show when running the ':show ipv6 route' command. As shown below.


Cisco867#show IPv6 route
IPv6 Routing Table - default - 5 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, ND - ND Default, NDp - ND Prefix
DCE - Destination, NDr - Redirect, a - Application
ND ::/0 [2/0]
via FE80::2D0:F6FF:FE38:8388, Ethernet0.101

I don't know whether I have the optimum config but it is working never the less. Sky don't provide IPv6 DNS servers. You can use the IPv4 DNS to do AAAA resolution or you can add in some public IPv6 DNS server details to do native IPv6 DNS resolution. I've used the Google IPv6 DNS in my config.

The Default Route is acquired via Router Advertisement / Solicitation. The IPv6 /56 prefix is acquired via DHCPv6.

These are the IPv6 config settings I've used.


ipv6 unicast-routing
ipv6 dhcp pool sky-ipv6pool
prefix-delegation pool sky-prefix
dns-server 2001:4860:4860::8888
dns-server 2001:4860:4860::8844
!
ipv6 cef
!
interface Ethernet0.101
encapsulation dot1Q 101
ipv6 enable
ipv6 nd autoconfig default-route
ipv6 dhcp client pd sky-prefix


interface Vlan1
ipv6 address sky-prefix ::1/64
ipv6 enable
ipv6 dhcp server sky-ipv6pool

If anyone seeing this can suggest some improvements please let me know.

Hope this helps someone else.

P.S. Shonk , I think your comments regarding limitation to throughput refer to the older 800 series routers not the 867VAE with embedded ADSL/VDSL controller.