[Dnsmasq-discuss] Cannot get IPv6 RA to occur

John Knight John.Knight at belkin.com
Tue Mar 7 19:57:27 GMT 2017


I am trying to get dnsmasq to send out IPv6 RAs to my LAN interface (br0), but can't seem to get it to work.  I have tried various configurations I have found on the internet, but to no avail.

I am using dnsmasq 2.76.  My router has WAN interface (eth0) that has an IPv6 global address that was configured via PD from RAs received from upstream router.  I am trying to use dnsmasq to service the LAN clients on br0, and to do this I want to enable dnsmasq router advertisements (RA).

Here is my current attempt at configuration:

I have also tried this:

And many other variants of the above.

The dnsmasq.log file shows the following:
DHCPv4-derived IPv6 names on br0
Router advertisement on br0
IPv6 router advertisement enabled

However, my LAN client attached to br0 does not receive an RA.  It never establishes a global IPv6 address.  I have also verified this using "tcpdump -I br0 | grep advert".  I see no advertisements on the br0 interface.

This does raise a few questions for me:

1)      How does dnsmasq learn of the prefix to use for the RA?  I want it to use the prefix received on the WAN interface (eth0) for the RA on the LAN interface (br0).  It is not clear to me how to configure this.

2)      The dnsmasq log file indicates "Router advertisement on br0".  Does this mean that it sent out the Router advertisement on br0?  I thought so, but alas, I do not see the RA on br0.

3)      With radvd, there are controls to determine the frequency of advertisements.  Are there any controls for dnsmasq?  What is the default frequency of RA advertisement?

4)      I only have the man page for dnsmasq.  Is there a User guide with more details on using dnsmasq?

5)      I am currently using radvd in the router, and I am thinking if I can get this to work, I will stop using radvd.  Are there any compelling reasons to use dnsmasq RA over radvd?

6)      What is the preferred/expected syntax for the dhcp-range?  I have seen a number of different variations and find it very confusing... even the two examples abover have different syntax.  Both seem to be accepted by dnsmasq.

I appreciate your help with this.  I hope to get this to work soon.


John Knight
John.knight at belkin.com<mailto:John.knight at belkin.com>

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