[Dnsmasq-discuss] What is the required configuration for enabling periodic RA's

Simon Kelley simon at thekelleys.org.uk
Fri Oct 25 16:38:12 BST 2013

On 25/10/13 16:28, Gordon Scott wrote:
> Hi there,
> I'm trying to use dnsmasq to provide RA for stateless IPV6 configuration.
> Does anyone know the configuration required to get dnsmasq to send out RA's
> periodically?
> So far I seem to only see RA's be sent after a DHCP request occurs.

How are you looking for the RAs? In some configurations, dnsmasq will 
unicast an RA after a DHCPv4 request, but the periodic RAs are always 
multicast. If you're looking at packets and only looking for unicast
packets, that would explain your observations.

Dnsmasq always logs each time it sends an RA, so it's worth looking in 
the system logs.

> I'm trying to set this up on a router that has a dynamic backhaul where the
> assigned IPV6 prefix can change abruptly.  I've seen problems in the past
> where clients such as Windows XP seem to ignore a single RA after an IP
> change.  The only way I've found to get this bullet proof is to use RADVD
> to periodically broadcast RAs.

For dynamic prefixes, you want something like


Which will pick up the address installed on the local interface by tyhe 
backhaul and advertise the subnet over that interface.



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