[Dnsmasq-discuss] IPv6 RA issues when bound to IPv4

Michal Zatloukal myxal.mxl at gmail.com
Thu Jul 16 16:27:53 BST 2015

Hi all,

I'm using dnsmasq (2.68-1ubuntu0.1) on a machine where the need to run
tftpd-hpa along with dnsmasq's own tftp server has arisen (both on
just IPv4). I decided to use the "secondary IP address" feature in
Linux networking system to bind tftpd-hpa to the secondary IP address,
and set up dnsmasq to bind the following:
- primary IPv4 address
- localhost IPv4
- For IPv6, I put in localhost, global and link-local addresses. IIUC,
RA can't work in this config, since the destination on RS is multicast
ff02::2 and therefore aren't delivered to any of the sockets opened by

Now, which IPv6 address do I enter so that IPv6 router announcements
work correctly? (Is it even possible?)
- adding ff02::2 doesn't work, dnsmasq reports error in syslog -
cannot bind to this address.
- replacing all IPv6 addresses with "::" allows dnsmasq to start and
bind to wildcard IPv6, but it seems incoming RS packets are ignored -
nothing appears in syslog when clients send solicitation. Is the
filtering code in DSNmasq perhaps not expecting a wildcard address in
the listen-address parameter and filters packets against it?



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