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

[Sivabalakrishnan M]

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.

Thanks,
Siva

[Albert ARIBAUD]

Hi,

Le Tue, 5 Apr 2016 18:48:37 -0700

Post by Sivabalakrishnan M
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?

Post by Sivabalakrishnan M
Thanks,
Siva

Amicalement,

[Sivabalakrishnan M]

The real mac address is - 00:50:56:96:42:c2. The prefix in question is
00:01:00:01:1e:97:03:eb:
(8 bytes).

Thanks,
Siva

On Tue, Apr 5, 2016 at 10:57 PM, Sivabalakrishnan M <

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.
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.
Thanks,
Siva

Post by Albert ARIBAUD
Hi,
Le Tue, 5 Apr 2016 18:48:37 -0700

Post by Sivabalakrishnan M
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?

Post by Sivabalakrishnan M
Thanks,
Siva

Amicalement,
--
Albert.

[Albert ARIBAUD]

Hi Siva,

Le Tue, 5 Apr 2016 22:57:10 -0700

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.
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

Post by Albert ARIBAUD
Hi,
Le Tue, 5 Apr 2016 18:48:37 -0700

Post by Sivabalakrishnan M
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?

Post by Sivabalakrishnan M
Thanks,
Siva

Amicalement,
--
Albert.

Amicalement,

[Sivabalakrishnan M]

Thanks a lot Albert. This helps.

Thanks,
Siva

Post by Albert ARIBAUD
Hi Siva,
Le Tue, 5 Apr 2016 22:57:10 -0700

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.
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

Post by Albert ARIBAUD
Hi,
Le Tue, 5 Apr 2016 18:48:37 -0700

Post by Sivabalakrishnan M
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?

Post by Sivabalakrishnan M
Thanks,
Siva

Amicalement,
--
Albert.

Amicalement,
--
Albert.