On Thu Dec 18 12:31:31 2014, jpopelka@redhat.com wrote:
> Hello,
> 
> by default, DHCPv6 dhclient creates DUID-LL
> if it is running in stateless mode (-6 -S) and
> doesn't write it into leases file, most likely
> because the DUID-LL is always generated the same.
> 
> It's however possible to specify DUID to be of type LLT instead of LL
> with '-D LLT'. Rfc 3315 says that:
> 'Clients and servers using this type of DUID MUST
> store the DUID-LLT in stable storage.'
> That's not fulfiled in this case (-6 -S -D LLT),
> because it's generated each time again.
> 
> It's not a big deal because the server doesn't store any
> info about 'stateless' clients, so it doesn't matter
> that the DUID-LLT is different each time.
> But there's a TAHI test which tests this, i.e. that
> DUID-LLT is still the same even in stateless mode.
> It's a test DHCP_CONF.7.1.9, part B.
> https://www.ipv6ready.org/docs/Phase2_DHCPv6_Conformance_Latest.pdf

=> very funny: one needs a test suite (note I like the TAHI test :-)
to discover such a problem. I don't know if the code has
the provision to save and get back the DUID-LLT in stateless
mode: if it is the case it will be easy to fix. If it is not,
perhaps it will be easier to clarify the RFC 3315 which
1- is currently under revision 2- was written before stateless
(and prefix delegation)...
Thanks anyway and merry Christmas!