[Dnsmasq-discuss] Dnsmasq - dnsmasq.leases IPv6 example

Sivabalakrishnan M sivabalakrishnan.m at gmail.com
Wed Apr 6 16:54:51 BST 2016


Thanks a lot Albert. This helps.

Thanks,
Siva

On Wed, Apr 6, 2016 at 12:26 AM, Albert ARIBAUD <albert.aribaud at free.fr>
wrote:

> Hi Siva,
>
> Le Tue, 5 Apr 2016 22:57:10 -0700
> Sivabalakrishnan M <sivabalakrishnan.m at gmail.com> a écrit:
>
> > Thanks much Albert for the reply. Sorry, I meant 6 bytes for MAC and
> > it was a typo. Please find more details below.
> >
> > We use --dhcp-script & --leasefile-ro options for maintaining lease
> > database instead of the default dnsmasq leases file. The issue that am
> > facing is -  the script is invoked by Dnsmasq daemon with mac address
> > of size of more than 6 bytes as you can see below. Our script
> > validates the mac address and since it exceeds the 6 byte, we return
> > error.
> >
> > Dnsmasq logs:
> > Apr  1 21:59:34 dnsmasq-dhcp[620]: DHCPSOLICIT(5)
> > 00:01:00:01:1e:97:03:eb:00:50:56:96:42:c2
> > Apr  1 21:59:34 dnsmasq-dhcp[620]: DHCPADVERTISE(5) 20:1::1:1b7
> > 00:01:00:01:1e:97:03:eb:00:50:56:96:42:c2
> > Apr  1 21:59:35 dnsmasq-dhcp[620]: DHCPREQUEST(5)
> > 00:01:00:01:1e:97:03:eb:00:50:56:96:42:c2
> > Apr  1 21:59:35 dnsmasq-dhcp[620]: DHCPREPLY(5) 20:1::1:1b7
> > 00:01:00:01:1e:97:03:eb:00:50:56:96:42:c2
> >
> > The mac address passed to script by Dnsmasq is also
> > 00:01:00:01:1e:97:03:eb:00:50:56:96:42:c2 for IPv6 address
> > 20:1::1:1b7. The actual mac address is :50:56:96:42:c2. But I don't
> > know how 00:01:00:01:1e:97:03:eb:00: gets prefixed to the real mac
> > address. This is the problem am facing now. Please let me know if
> > this is expected in any scenario or if not, what could be the issue
> > here? Any help on this is really appreciated.
>
> Look up man dnsmasq, and more specifically the --dhcp-script option.
> You'll see that for IPv4 the MAC address is passed, but for IPv6, it is
> the DUID, which is 12 to 20 bytes depending on the exact situation --
> in your case it seems to be 14 bytes.
>
> > Thanks,
>
> NP, HTH.
>
> > Siva
> >
> > On Tue, Apr 5, 2016 at 10:40 PM, Albert ARIBAUD
> > <albert.aribaud at free.fr> wrote:
> >
> > > Hi,
> > >
> > > Le Tue, 5 Apr 2016 18:48:37 -0700
> > > Sivabalakrishnan M <sivabalakrishnan.m at gmail.com> a écrit:
> > >
> > > > Hi,
> > > >
> > > > Could anyone please share the sample output of dnsmasq.leases file
> > > > for IPv6 entries? Is it possible to have mac address with size
> > > > more than 8 bytes for IPv6? Please let me know.
> > >
> > > MAC addresses are standard, have 6 bytes, not 8, and do not differ
> > > in IPv6 from what they are in IPv6.
> > >
> > > Are you maybe referring to the EUI-64 format address in SLAAC ? But
> > > that too is fixed-format, so you cannot have an EIU-64 address
> > > longer (or shorter, for that matter) than 8 bytes.
> > >
> > > Can you expand on what the actual problem is that you are
> > > encountering?
> > >
> > > > Thanks,
> > > > Siva
> > >
> > > Amicalement,
> > > --
> > > Albert.
> > >
>
>
>
> Amicalement,
> --
> Albert.
>
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