[Dnsmasq-discuss] Need some indications to patch dnsmasq, to bypass /64 limit

Simon Kelley simon at thekelleys.org.uk
Thu Nov 21 12:46:26 GMT 2013


On 16/11/13 09:08, dnsmasq.bertrandb at dfgh.net wrote:
>> You should be able to configure DHCPv6 in dnsmasq to handle larger
>> prefixes. You can't do SLAAC address allocation that way, because it
>> depends on a 64-bit prefix and a 64-bit EUI-64 id, but DHCP works.
>>
>> Something like
>>
>> dhcp-range=<start-address>,<end-address>,92
>>
>> The prefix length MUST match the prefix length configured in the local
>> inerface.
>
> Thanks for the response i try
> I make the modification on /var/lib/libvirt/dnsmasq/reseau.conf and kill
> up the process
> so my dnsmasq.conf is :
> ##WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
> ##OVERWRITTEN AND LOST. Changes to this configuration should be made using:
> ## virsh net-edit default-ipv6
> ## or other application using the libvirt API.
> ##
> ## dnsmasq conf file created by libvirt
> strict-order
> domain-needed
> domain=root.belguise.eu
> expand-hosts
> local=/root.belguise.eu/
> pid-file=/var/run/libvirt/network/default-ipv6.pid
> except-interface=lo
> bind-dynamic
> interface=virbr0
> dhcp-range=192.168.122.2,192.168.122.254
> dhcp-no-override
> dhcp-range=2a00:c70:1:xxx:xxx:xxx:8106:901,2a00:c70:1:xxx:xxx:xxx:8106:f01,97
>
> dhcp-leasefile=/var/lib/libvirt/dnsmasq/default-ipv6.leases
> dhcp-lease-max=1790
> dhcp-hostsfile=/var/lib/libvirt/dnsmasq/default-ipv6.hostsfile
> addn-hosts=/var/lib/libvirt/dnsmasq/default-ipv6.addnhosts
> #enable-ra
>
> mybridge is on same prfix
> root at root:~# ifconfig virbr0
> virbr0 Link encap:Ethernet HWaddr 52:54:00:89:5a:8e
> inet adr:192.168.122.1 Bcast:192.168.122.255 Masque:255.255.255.0
> adr inet6: 2a00:c70:1:xxx:xxx:xxx:8106:ffff/97 Scope:Global
>
> and I got
> Nov 16 09:53:51 root dnsmasq-dhcp[2371]: no address range available for
> DHCPv6 r
> equest via virbr0
>
> if I change the prefix in /64 i see an RTR-ADVERT in log
> not with /97 (i'd try with /112 too)
> I think that dhclient on my vm's send an RTR-SOLLICIT whish is the
> origin of the message and don't send DHCP stuff since there is no
> reponse to is RTR-SOLLICIT
>
> On my vm (debian wheezy) my /etc/network/interfaces is
>
> iface eth0 inet6 dhcp
> accept-ra 0
> autoconf 0
>


What version of dnsmasq are you using? I just tried this with the latest 
code, and didn't see this error.

Cheers,

Simon.



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