IPv6 routing issue

[John Blakley]

All,

I'm testing ipv6 dhcp pools, and it's working (I believe). I have a Windows XP host that's getting a default gateway of FE80::8c29. Before I configured DHCPv6, I wasn't getting a default gateway at all.

I have 6to4 tunnels configured between two routers, and I have loopbacks created on the far router. I have OSPFv3 running across the tunnels, and this is definitely working.

My problem is that from my XP host, I can't ping any of the loopbacks on the far router. My default gateway router has the far loopback addresses and I can ping them from my default gateway, but not from the host. What can be the cause of this? Is it the link-local addresses causing the problem?

Thanks!

John

[Laurent Aubert · Accepted solution]

Hi John,

Your host needs a global IPv6 address which can be routed over your tunnel. The remote router needs to learn this subnet as well via OSPFv3.

You have the choice between stateless or stateful DHCP implementation:

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-dhcp.html#wp1055674

HTH

Laurent.

[John Blakley]

Thanks Laurent, that's what I figured. The host isn't getting a dhcpv6 address. I don't think I have it configured correctly, and I'm still playing with it. I'm assuming, like in ipv4, my dhcp scope will need to match the prefix that's assigned to an interface on the router?

Thanks!

John

[Giuseppe Larosa]

Hello John,

sorry for the basic question:

is the XP host getting an ipv6 address from the pool that is not a link local ?

second:

is the DHCPv6 pool advertised in some manner over OSPFv3 ?

you may need a loopback with an ipv6 address that represents the pool and to advertise it

Hope to help

Giuseppe

[John Blakley]

By all means Giuseppe, be basic =)

I'm actually not getting my address assigned via DHCP; I only have a link-local address. The gateway for the host is set to the router's link local address as well, but I realized that it's getting that address from the RS (maybe NS in this case?). So, something still isn't right with my DHCPv6 pool on the router.

Thanks,

John

[Laurent Aubert]

You should remove your DHCPv6 configuration and implement only stateless autoconfiguration and see if it works.

Laurent.

[John Blakley]

Laurent,

That worked, and my 6to4 tunnels are working. :) BUT, how would I assign addresses for my hosts like in DHCP for ipv4? Let's say that I was assigned the block of:

2001:1111:1111::/48

How can I assign the prefix to clients and have them autoconfigure based off of what the DHCP server gives them? I have another post out there that explains that I'm not seeing any traffic with wireshark from the host that I wanted to get a dhcp address for. All it's sending is NS packets and I get an NA back from the router. I don't see any DHCP discover packets.

Thanks!!!

John

[Giuseppe Larosa · Accepted solution]

Hello John,

follow this chapter on ipv6 configuration guide.

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-dhcp.html#wp1054245

Make also a search in the forums there have been other threads about dhcpv6 some time ago with answers from Harold Ritter.

Hope to help

Giuseppe

[Giuseppe Larosa]

hello John,

I've found the thread I was meaning

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=LAN%2C%20Switching%20and%20Routing&topicID=.ee71a04&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40^1%40%40.2cd25c69/1#selected_message

March 16 2009

Hope to help

Giuseppe

[Laurent Aubert]

John,

You need to configure the router as a DHCPv6 server as described in the configuration guide I provided in my first post.

Also XP doesn't support DHCPv6 client, you need an external client like this one:

http://klub.com.pl/dhcpv6/

HTH

Laurent.