[Cerowrt-devel] coping with ipv6 source routing and dns

Dave Taht dave.taht at gmail.com
Wed Jan 29 14:22:16 EST 2014

I have been (mostly) happily fiddling with my new comcast ipv6 connection,
trying to route all dns queries over ipv6 in particular, by disabling
requesting the ipv4 dns addrs and relying on the dhcpv6 request to

config interface eth0
        option 'ifname' 'eth0'
        option 'proto'  'dhcp'
        option 'peerdns' '0'

config interface wan6
        option ifname   @eth0
        option proto    dhcpv6
        option 'broadcast' '1'
        option 'metric' '2048'

works. yea! no more nat holes for ipv4 dns.

Problem is, I also have a hurricane electric tunnel. When I try to use
both, addresses from one get used on the other and dns forward
lookups fail.

I think the right answer is to abandon resolv.conf.auto
and instead explicitly assign ipv6 source addrs in dnsmasq...

server=2001:558:feed::1 at AAAA:comcast:assigned:ipv6:address
server=2001:558:feed::2 at AAAA:comcast.assigned:ipv6:address
server=2001:470:20::2 at my:hurricane:assigned:ipv6:address

yes? (I'll be trying this in a bit)

One thing of possible useful note is that (yea!) we can just
select some arbitrary new ipv6 address within the assigned range,
add it to the local dnsmasq server box, and source dns lookups from
that, using up just that port space.

then my own /etc/resolv.conf just points to localhost
for hm.armory.com,

so I fix that with


But this doesn't help in terms of reverse lookups (I think),
where I might or might not have my own delegated subdomain.


comcast.assigned.ipv6.address.range/60 lookup via 2001:558:feed::1 or ::2
he.assigned.ipv6.address.range/48 lookup via 2001:470:20::2


and then there's splitting dns... where I might want nuc.hm.armory.com
AAAAs available to the outside universe. somehow.


My brain hurts.

Dave Täht

Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html

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