Hmm interesting thanks.  It might be better if instead of exiting dhclient just waited for a link local address, or had an option to do that.  I can add that and submit a patch back to isc.  Otherwise I'll need to write a wrapper around dhclient to do the same thing.

This is for an embedded system so I doubt debian is going to fix it for us.  :)



On Sat, Oct 4, 2014 at 5:59 PM, Chuck Aurora via RT <dhcp-bugs@isc.org> wrote:
On 06/02/2014 01:21 PM, John Newlin via RT wrote:
> If dhclient -6 is started immediately after ifup, dhclient exits
> with the message:
> [ 19.510927] dhclient6.wan0: Can't bind to dhcp address: Cannot assign
requested address
> [ 19.510954] dhclient6.wan0: Please make sure there is no other dhcp server
> [ 19.510970] dhclient6.wan0: running and that there's no entry for dhcp or
> [ 19.510987] dhclient6.wan0: bootp in /etc/inetd.conf. Also make sure you
> [ 19.511003] dhclient6.wan0: are not running HP JetAdmin software, which
> [ 19.511017] dhclient6.wan0: includes a bootp server.
>
> If I wait a bit and run it, it runs fine. I think it's because
> when the interface comes up the local link address is marked
> "tentative" and not really usable until the multiple address
> detection has finished running.

Hi John, thank you for the report, and please accept my apology
for the long delay in response. This was assigned to me back in
June, and actually a bit before that because someone was asking
what was fundamentally the same question in response to a post
on our ISC.org blog. It got lost among other issues.

The answer is: you are right. IPv6 must first be enabled on an
interface before you can use DHCPv6. If there is a delay in
your link-local address coming up, your OS should wait before
trying to run "dhclient -6". (Perhaps this is worth filing a
bug with Debian?)

This new Knowledge Base article explains it:

https://kb.isc.org/article/AA-01212

Thanks again for the report, and for your use of and interest in
ISC software. I am marking this bug as resolved.
--
Chuck Aurora : ISC Software Support : chucka@isc.org
Internet Systems Consortium, Inc.