[Dnsmasq-discuss] ipv6 - How to add static route with metric

Daniel tech at tootai.net
Fri Sep 10 07:50:04 UTC 2021

Hello Petr

Le 10/09/2021 à 00:10, Petr Menšík a écrit :
> Hello Daniel,
> dnsmasq --help dhcp6
> does not list options 3 and 6. According to Iana list [1], those are
> OPTION_IA_NA and OPTION_ORO. It does not seem they are correct for IPv6.
> I can see there plenty of options, but did not find way to specify IPv6
> route. Are you sure the target router for the route should not use
> router advertisement to propagate its routes instead? Would you
> describe, what are you trying to archieve? Why should have clients have
> some route instead of router for the network?

I'm in a phase of replacing OpenVPN with wireguard as well as replacing 
ipv4 with ipv6 in the network.

I have 2 routers in the office network: UTM Sophos as firewall in a VM 
as default GW, another VM running Debian11 which do the routing job 
(VPNs, DNS, aso) usind dnsmasq & bind as GW for VPNs (I have 3 servers 
in DC which are connected through VPN to this network, each of them 
having VMs).

I setup some only ipv6 desktops, the Debian VM acting for NAT64. 
Everything works perfect except that only ipv6 desktops can't reach what 
is in DC behind VPNs as there default route point to UTM Sophos. If I 
manually ip -6 r add <network> via <ipv6 Debian11> dev lan it works.

I could add manually this command for one desktop, but for many ... 
that's why I was looking for a solution with dnsmasq.

> Could --ra-param help instead?

ra is enabled on both routers. I will modify the dnsmasq setup so the 
default route would be to set to DebianVM for those machines.

Thanks for your help.

> On 9/9/21 11:22 AM, Daniel via Dnsmasq-discuss wrote:
>> Hello,
>> using dnsmasq for office network, I would like to add an ipv6 static
>> route. My configuration looks like
>> dhcp-range=set:computer6, fd00:5678:beef:cafe::ff:0,
>> fd00:5678:beef:cafe::ff:ffff, slaac, ra-names, 1h
>> dhcp-option=tag:computer6,option6:3,fd00:5678:beef:cafe::2
>> dhcp-option=tag:computer6,option6:6,fd00:5678:beef:cafe::1
>> dhcp-option=tag:computer6,option6:ntp-server,fd00:5678:beef:cafe::2
>> Now I want to add route like <destination network,metric,GW>
>> dhcp-option=tag:computer6,option6:3,fd00:5678:beef:cafe:fade::/96,192,fd00:5678:beef:cafe::1
>> but this does not work (also tried <GW,metric,destination network>
>> What am I doing wrong ?
>> Thanks for your support

Daniel Huhardeaux
+33.368460088 at tootai.net	      sip:820 at sip.tootai.net
+41.445532125 at swiss-itech.ch		    tootaiNET

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