Choosing an open source DHCPv6 client

Bjørn Mork bjorn at mork.no
Wed Oct 19 12:09:00 CEST 2011


Vikram Agrawal <vikram.agrawal at ipinfusion.com> writes:

> Thanks for the inputs.
> I have stuck to using ISC DHCP client.
>
> But there's another thing which I figured was not working on ISC DHCP Client
> which is;
>
> ISC DHCP Client - Does not pick up the cilent duid from config file.
>
> isc-dhclient-4.1.1-P1 did not allow for any duid specific configuration on
> the command line.
> Dhclient - isc-dhclient-4.2.2 is better in the sense that it provides an
> option -D to pick up either the LL or LLD.
> The DUID taken is either the LL ( link layer) or the LLT (link layer with
> timestamp).
>
> The dhclient.conf file states that the duid could be provided with a
> send dhcp-client-identifier <address>

It does?  Not in mine.  dhcp-client-identifier is a DHCP option.  The
DHCPv6 client DUID option name is dhcp6.client-id. But configuring it is
not supported.  From dhcp-options(5):

     option dhcp6.client-id string;

         This option specifies the client's DUID identifier.  DUIDs are
         similar but different from DHCPv4 client identifiers - there
         are documented duid types:

         duid-llt

         duid-en

         duid-ll

         This value should not be configured, but rather is provided by
         clients and treated as an opaque identifier key blob by
         servers.



Anyway, supported or not, I just tested setting

 send dhcp6.client-id 0:1:0:1:16:31:5b:6e:2:0:a:b:c:d;

in dhclient.conf and it does work as expeced.  You should be careful,
though.  The DUID scheme is created to ensure unique IDs, and
configuring them are guaranteed to screw up this at some point...

Why can't you use the standard LL or LLD scheme?


Bjørn


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