[Dnsmasq-discuss] IPv6 routes with length between 1 and 63

David Mandelberg david at mandelberg.org
Fri Oct 22 22:32:14 UTC 2021


Hi,

I'm trying to configure interfaces where dnsmasq offers addresses 
(DHCPv4, SLAAC, and DHCPv6), on-link prefixes (DHCPv4 and RA), and 
routes via itself to off-link prefixes, but no default routes.

For DHCPv4, I've got this (not yet tested):

dhcp-option=tag:routesLocal,option:router
dhcp-option=tag:routesLocal,option:classless-static-route,10.0.0.0/8,0.0.0.0
dhcp-range=set:routesLocal,10.X.Y.Z,10.U.V.W

For DHCPv6/RA, I've got this:

enable-ra
ra-param=infra,0,0
dhcp-range=tag:routesLocal,fdXX:XXXX:XXXX::,off-link,48
dhcp-range=set:routesLocal,fdXX:XXXX:XXXX:YYYY::100,fdXX:XXXX:XXXX:YYYY::1ff,slaac
dhcp-range=set:routesLocal,::,constructor:infra,slaac

And I'm getting this error from the off-link line:

prefix length must be at least 64 at line 49 of /etc/dnsmasq.conf


So my questions are: Is off-link the right way to advertise an IPv6 
prefix that should be routed via the host dnsmasq is running on? If it 
is, why is it restricted to length 64 or greater? I understand why 
on-link prefixes shouldn't be too short, but doesn't this just affect 
the routing table, which can handle shorter prefixes?



More information about the Dnsmasq-discuss mailing list