Greetings,

I have Comcast and they do DHCP-PD and support IPv6.  I set up a DHCP scope to be used (along with the proper options) for addressing computers within my subnet, figuring that they would also get a 2601:/64 address from the router.  Unfortunately what is happening is that unless I specify the subnet address, DHCP is being ignored anyways.  I currently have both the M and O flags set to true.

Any suggestions on getting the address from the Router AND the subnet addresss with options to be used and recognized by my client computers?

Thanks,

Bob Hessenauer

Perhaps the ISP would help you.

I do not fully understand which DHCP do you mean, on router/modem or on server (you have placed your question into server forum...)

What security model do you use in your infrastructure (AD,...)?

Regards

Milos

I am using AD, and want the DHCPv6 Server on the PDC to be distributing IPv6 addresses for the computers within my subnet.  Unfortunately once they get an address from the router (which is global) they do not look to the AD Server for anything else.

Hope this helps in answering your question

Bob Hessenauer

In my understanding in client computers there is DNS setting that points to DNS on DC (no other value of DNS IP is in NIC settings). If domain DNS is configured properly, then there are parameters that point to proper DHCP server. And more, you can disable DHCP server in router configuration.

HTH

Milos

For IPv4 you are correct, but that is not the case when you are talking about IPv6.  IPv6 gets infotrmation through router advertisement and I am trying to set mine so the router gets a global IPv6 address and the machines inside only use the subnet that I have defined in DHCPv6.

Hope this helps,

Bob Hessenauer

Here is what I am looking for:

Global IPv6 IP from Comcast--Router (M-? o-? PD - off)--fdc8::1 Subnet IPv6---DHCP Server passing out fdc8/64 addresses

Any Thoughts? I am trying to NOT have my Internal machines get a Globally Accessable IPv6 Address

Bob Hessenauer

RA's for Stateful (DHCPv6) need A flag off, M & L flags on, (O doesn't matter in this case as M does addr and "other info" like O).

Just to be clear, fdc8::/64 is a ULA address, is not routed to outside world (liken [but not exactly] to RFC 1918), unless you have NPTv6 or some device converting ULA->GUA.

You may actually need to turn RA's totally off on the Comcast router and configure another router to send RA's like you require. Could be the Windows server, altho tuning its RA's is not as granular as a "real" router.

Would help to see a trace. If you use Wireshark, set display filters "icmpv6.type == 134 or dhcpv6". then mark those pkts and save out just those few. Seeing the RAs and the DHCPv6 Solicit/Advertise/Request/Reply pkts will tell alot.

BTW, Comcast has been doing this a long time, I would think they would have all the info needed to achieve your goal....hmmm....I'd love to have Comcast as my ISP! (ISPs in DFW,TX metro area don't do IPv6 for home/SMB and don't have a public announced plan when)

hth...Jeff

Hi,

Please make sure that you have set the M and O flag to true in the router's RA. Whether the client obtain the stateful IP address and other configuration depends on the recieved RA's M and O flag.

Or we can try to disable the RA from the router. The DHCPv6 server will send the RA according to your configuration.

For detailed information about how does Windows client get the IPv6 configuration, please refer to the link below:

https://technet.microsoft.com/en-us/magazine/2007.08.cableguy.aspx

To download Network Monitor, please click the link below:

http://www.microsoft.com/en-hk/download/details.aspx?id=4865

Best Regards.