KVM instance network broken when using IPv4 DHCP and IPv6 SLAAC

[bahamat]

My network is primarily IPv6. IPv4 is only used for legacy connectivity but all "real" management and operation runs over IPv6.

KVM instances constantly complain:

IPv6: eth0: IPv6 duplicate address 2001:db8::c046:a8ff:feba:a41a detected!

This happens with every KVM instance I create.

My nic configuration is:

"nics": [
  {
    "nic_tag": "admin",
    "ip": "dhcp",
    "primary": "true",
    "allow_ip_spoofing": "true"
  }
],

• When I ping the IPv6 address I get no response.
• There is no IPv4 address configured on the interface.

I have tried with both cents-6 and debian images, about 20 times and all have had the same behavior:

# imgadm list
UUID                                  NAME          VERSION  OS       PUBLISHED           
94384a12-bbeb-11e2-aec2-2bfa9742484b  debian-6.0.7  2.4.2    linux    2013-05-13T19:19:01Z
30e9e4c8-bbf2-11e2-ac3b-3b598ee13393  centos-6      2.4.2    linux    2013-05-13T19:42:33Z

[rmustacc]

Regarding IPv6, see TritonDataCenter/illumos-kvm-cmd#13. Regarding IPv4 while that looks like a simple configuration (you don't need allow_ip_spoofing, that comes with dhcp), I'm not sure that those images are configured off hand to attempt dhcp. Does the guest VM appear configured for v4 networking? Did your dhcp server appear to get any packets for it. What happens if you manually tell the nic to do dhcp say via dhclient eth0 or dhcpcd eth0 or whatever the appropriate method is for the Linux distros in question.

[bahamat]

For IPv6, that looks like it's affecting me. Is there a temporary workaround that I can put in place today?

For IPv4, yes, DHCP is configured properly and dhclient is running on eth0. I've traced my DHCP server and I can see the DHCPREQUEST come in, an IP is chosen, a lease assigned and the DHCPOFFER is sent.

Using snoop in the global zone I don't see any DHCPOFFER.

And of course, everything else on my network using DHCP works fine.

[bahamat]

Resolved on my local side. DHCP issues were not caused by SmartOS.

[trinhpham]

Although it's not caused by SmartOS but it would be helpful if you can post your solution here.

PS: I'm facing this problem, and Google takes me here with no solution T_T

[bahamat]

The duplicate address was a bug in SmartOS that was fixed long ago. If you’re still running something from 2013 you need to upgrade.

The dhcp issue was a problem on the dhcp server. In my case an SRX hardware appliance, so almost certainly not relevant to you.

[trinhpham]

Thanks for your kind reply, @bahamat
I figure out that the problem comes by one of my DHCP relay server. Don't know the reason, but restart it get the issue fixed.