IPv6 Dial Access

[amir_taghavi]

Hi,

I have some dialup users, but they are not recieving any IPv6 when dialing to the router. IPv4 connection is fine. If I put static IPv6 on windows(win7) dialup connection is working, but it's not reciving IPv6  via IPCPv6 automatically.

Here is configuration.

Thank you for your help :

[andrew.butterworth]

I am doing something similar but with VPN so I assume this will work.

Change this line 'peer default ipv6 pool AMIRV6' to point to the ipv6 local pool you have named 'v6'.

My Virtual-Template interface looks like this:

interface Virtual-Template10

ip unnumbered Loopback0

ip flow monitor IPv4-Output-Flow-Monitor output

ip virtual-reassembly in

peer default ip address pool default

peer default ipv6 pool VPN

ipv6 enable

no ipv6 nd ra suppress

ppp authentication ms-chap-v2 PPP-VPN

ppp ipv6cp address unique

!

ipv6 local pool VPN 2001:xxx:xxxx:xxxx::/64 64

One thing that doesn't work though is passing the IPv6 DNS server addresses to the client via IPv6CP, with IPv4 this was done with the command 'async-bootp dns-server x.x.x.x y.y.y.y'.  According to this it is an optional part of the IPv6CP standard - http://tools.ietf.org/html/draft-huang-ipv6cp-options-00.

Andy

[Phillip Remaker]

This blog might help:

http://blog.ioshints.info/2011/03/ipv6cpdhcpv6slaacra-ipcp.html

For a set of useful clues in getting IPv6 working on a dial link.

[andrew.butterworth]

Hi Philip

I must admit I don't keep up with too many RFC's but I was hoping RFC5072 had been superceeded (or added to) to include DNS in IPv6CP.  If you have a read of the link I posted (http://tools.ietf.org/html/draft-huang-ipv6cp-options-00) it discusses options for primary & secondary DNS (like we have with IPCP).  This obviously needs implementing in both the client & server but I thought (hoped?) it had already been included in current IOS & Windows 7.

I have managed to work around it by taking some of Ivans recommendations and combining IPv6CP & DHCP.  My configuration looks like this now for the virtual-template:

interface Virtual-Template10
ip unnumbered Loopback0
ip flow monitor IPv4-Output-Flow-Monitor output
ip virtual-reassembly in
peer default ip address pool default
peer default ipv6 pool VPN
ipv6 enable
ipv6 nd other-config-flag
no ipv6 nd ra suppress
ipv6 dhcp relay destination 2001:xxxx:xxxx:xxxx::1 Vlan99
ppp authentication ms-chap-v2 PPP-VPN
ppp ipv6cp address unique

ipv6 local pool VPN 2001:xxx:xxxx:xxxx::/64 64

I already had a DHCPv6 server (Windows 2008 R2) that is supporting my various networks.  I didn't add anything to this server and the client is now getting the IPv6 DNS servers and IPv6 Domain Suffix.  I have put wireshark on the inside interface of my access router and I can see the DHCPv6 relay messages (one in 'relay-forward' and one out 'relay-reply').  I can see that the client doesn't request interface address information and just asks for Domain search list, DNS recursive name server, Vendor-specific Information and Lifetime.

Andy

[Phillip Remaker]

Glad to hear it worked out.  I think that the idea of putting common configuration information in PPP Control Protocols is becoming increasingly obsolete at this point.  At the time that IPCP was developed, DHCP servers had not reached the state of ubiquity that they have reached today.  DHCP is really a more logical place to maintain that information in most cases, especially for DHCPv6 stateless DHCP.

Presumably, if you want to manage these parameters on a per user basis, the Control Protocol would be a better choice using a some back end server to dole out the parameters.  The administrative overhead to benefit ratio doesn't seem to work out.

Is the solution sufficient for your use case or do you have greater needs?