Linux – How to assign multiple IPv6 addresses with DHCPv6 to a single interface

dhcpipv6linuxpcap

This seems to be possible based on the spec rfc 3315 page 23:

Excerpt:

The configuration information in an IA consists of one or more IPv6
addresses along with the times T1 and T2 for the IA. See section
22.4 for the representation of an IA in a DHCP message.

Yet, I haven't been able to configure my DHCPv6 client to request these multiple IP addresses on an interface.

Does anyone know how to do this for a Linux DHCPv6 client (preferably running RedHat 6+, CentOS 6+, or Fedora), or on Windows?

My end goal is to do some testing with PCAP files. I would prefer to be able to generate these files myself, but if I can't get my client configured, I would like to find some PCAP files on the internet that I could use. So far, I haven't found anything.

Thanks!

Best Answer

I haven't tried this, but here's what I think would work:

Use brctl addbr to create a virtual switch. Create two virtual interfaces (with commands like ip tuntap add mode tap). Then add both tap interfaces and your physical interface to the bridge (e.g. brctl addif tap0). Now you have two interfaces on which to run dhcp clients.

Related Solutions

Why use DHCPv6 over Stateless Address Autoconfiguration

DHCPv6 provides more control to the administrator in assigning addresses. If you really want that sort of control over your IPv6 addresses, you don't understand IPv6 yet.

It also can be used to provide additional configuration parameters beyond the basic address/gateway supported through autoconfiguration. An example might be WINS servers, NTP servers, TFTP boot servers, and other less common options. None of which are worth the pain of deploying a DHCPv6 architecture in my opinion.

Stick with autoconfig.

How to configure radvd, dhcpd6, routing and /64 subnet based on delegated prefix by DHCPv6-PD server

I don't know the answer to your question, but I just want to warn you about using the DHCP server address as your default router. If that works it is by chance... In IPv6 the default route is communicated by RA's and not by DHCP.

You will need to enable forwarding, accepting RA's and sending out RS's. A problem here is that the kernel included in Centos6 does not allow you to do that. When forwarding is enabled then accepting RA's and sending RS's is disabled. There should be a CentosPlus kernel with the relevant patches though. See the mailing list thread / message at http://lists.centos.org/pipermail/centos/2011-April/thread.html#109756

The relevant sysctl.conf settings are:

net.ipv6.conf.all.forwarding=1
net.ipv6.conf.eth0.accept_ra=2
net.ipv6.conf.eth0.accept_ra_defrtr=1
net.ipv6.conf.eth0.router_solicitations=1

Best Answer

Related Solutions

Why use DHCPv6 over Stateless Address Autoconfiguration

How to configure radvd, dhcpd6, routing and /64 subnet based on delegated prefix by DHCPv6-PD server

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