[Dnsmasq-discuss] Need help configuring dhcp stateful IPv6

[Andre Coetzee]

--- On Fri, 18/5/12, Simon Kelley <simon at thekelleys.org.uk> wrote:
>
>From: Simon Kelley <simon at thekelleys.org.uk>
>Subject: Re: [Dnsmasq-discuss] Need help configuring dhcp stateful IPv6
>To: dnsmasq-discuss at lists.thekelleys.org.uk
>Date: Friday, 18 May, 2012, 12:10
>
>On 18/05/12 09:59, Andre Coetzee wrote:
>> When I set my dhcp-range option in dnsmasq.conf with a prefix-length of
>> 123, I get an "inconsistent DHCPv6 range" error. setting this value to
>> 125 or greater seems to work, also setting it to 120 or less seems to be
>> acceptable to dnsmasq.
>> 

<snip>

>> When I enable networking on a client machine (linux), I see
>> "RTR-SOLICIT(eth0)" messages in the logs, but no responses or
>> advertisements coming from the dnsmasq machine.
>> 
>
>OK, first thing, your post took me straight to an embarrassing bug: it's
>all broken if the prefix length is NOT divisible by 8 - all bets are off
>in that case.
>
>How is the relevant interface configured? The
>prefix length there must  match that configured into dnsmasq.
>
>
>Cheers,
>
>Simon.
>

Thank you Simon for this valuable information. Changing the prefix in the conf file 
to /120 and also changing the subnet mask on the interface to match (and restarting dnsmasq)
now results in router advertisements and dhcp addresses being issued.

May I suggest that the "prefix must be divisible by 8" caveat be documented in the man page
either in the section where the dhcp-range IPv6 prefix length option is discussed,
or under a new section "BUGS/KNOWN ISSUES"?

Many thanks
Andre