[Dnsmasq-discuss] DNSMasq doesn't see DHCPv6 Solicit msg

[Simon Kelley]

On 29/07/13 16:36, Shixiong Shang wrote:
> Hi,
>
> I am using DNSMasq to assign IPv6 address to client machine (Centos 6.4).
> Based on sniffer trace, I can see DHCP Solicit msg from client addressed to
> ff02::1:2 at UDP port 547:
>
> 11:18:25.140542 IP6 (hlim 1, next-header UDP (17) payload length: 60)
> fe80::f816:3eff:fe95:2389.546>  ff02::1:2.547: [udp sum ok] dhcp6 solicit
> (xid=e14b62 (client-ID hwaddr/time type 1 time 428180465 fa163e952389)
> (option-request DNS-server DNS-search-list) (elapsed-time 1652) (IA_NA
> IAID:1049961353 T1:3600 T2:5400))
>
>
> I changed the default configuration of dnsmasq and it is listening to port
> 547:
>
> root     19991 19990  0 11:09 ?        00:00:00 dnsmasq --no-hosts
> --no-resolv --strict-order --bind-interfaces --interface=ns-7f72b3ad-1a
> --except-interface=lo
> --pid-file=/var/lib/quantum/dhcp/81c3767a-d471-4433-8860-9a5ea20d4bd6/pid
> --dhcp-hostsfile=/var/lib/quantum/dhcp/81c3767a-d471-4433-8860-9a5ea20d4bd6/host
> --dhcp-optsfile=/var/lib/quantum/dhcp/81c3767a-d471-4433-8860-9a5ea20d4bd6/opts
> --dhcp-script=/usr/bin/quantum-dhcp-agent-dnsmasq-lease-update
> --leasefile-ro --enable-ra --port=547
> --dhcp-range=set:tag0,2001:192:168:2::,slaac,120s
> --dhcp-range=set:tag1,192.168.2.0,static,120s --conf-file=
> --domain=openstacklocal
>
>
> However, dnsmasq only saw IPv6 DHCP request from the VM, but not DHCPv6
> Solicit msg. Is there anything I did wrong?
>
> Jul 29 11:25:34 net-network1 dnsmasq-dhcp[19990]:
> DHCPREQUEST(ns-7f72b3ad-1a) 192.168.2.3 fa:16:3e:95:23:89
> Jul 29 11:25:34 net-network1 dnsmasq-dhcp[19990]: DHCPACK(ns-7f72b3ad-1a)
> 192.168.2.3 fa:16:3e:95:23:89 192-168-2-3
> Jul 29 11:25:47 net-network1 dnsmasq-dhcp[19990]:
> RTR-ADVERT(ns-7f72b3ad-1a) 2001:192:168:2::
> Jul 29 11:25:47 net-network1 dnsmasq-dhcp[19990]:
> RTR-ADVERT(ns-7f72b3ad-1a) 2001:192:168:2::
> Jul 29 11:25:49 net-network1 dnsmasq-dhcp[19990]:
> RTR-SOLICIT(ns-7f72b3ad-1a) fa:16:3e:95:23:89
> Jul 29 11:25:49 net-network1 dnsmasq-dhcp[19990]:
> RTR-ADVERT(ns-7f72b3ad-1a) 2001:192:168:2::
> Jul 29 11:25:50 net-network1 dnsmasq-dhcp[19990]:
> DHCPREQUEST(ns-7f72b3ad-1a) 192.168.2.3 fa:16:3e:95:23:89
> Jul 29 11:25:50 net-network1 dnsmasq-dhcp[19990]: DHCPACK(ns-7f72b3ad-1a)
> 192.168.2.3 fa:16:3e:95:23:89 192-168-2-3
> Jul 29 11:25:53 net-network1 dnsmasq-dhcp[19990]:
> RTR-SOLICIT(ns-7f72b3ad-1a) fa:16:3e:95:23:89
> Jul 29 11:25:53 net-network1 dnsmasq-dhcp[19990]:
> RTR-ADVERT(ns-7f72b3ad-1a) 2001:192:168:2::
> Jul 29 11:25:57 net-network1 dnsmasq-dhcp[19990]:
> RTR-SOLICIT(ns-7f72b3ad-1a) fa:16:3e:95:23:89
> Jul 29 11:25:57 net-network1 dnsmasq-dhcp[19990]:
> RTR-ADVERT(ns-7f72b3ad-1a) 2001:192:168:2::
>
>
> Thanks!
>
> Shixiong
>


You don't need to set the port, it uses 547 for DHCPv6 automatically. 
The --port=547 will change the port used for DNS, which is not what you 
want at all.


The reason that dnsmasq is not listening on 547 is that you've not 
configured it to do DHCPv6

--dhcp-range=set:tag0,2001:192:168:2::,slaac,120s

Only enables RA.

Try

--dhcp-range=set:tag0,2001:192:168:2::,static,120s
--enable-ra

or

--dhcp-range=set:tag0,2001:192:168:2::2,2001:192:168:2::400,120s
--enable-ra

if you want dynamic DHCP address allocation.


Cheers,

Simon.