[Dnsmasq-discuss] DHCPv6 + dhcp-relay + dhcpcd

[Petr Menšík]

Hello!

I were just debugging one of our old tests, which tested whether dnsmasq 
--dhcp-relay worked. Both for IPv6 and IPv4 addresses. But that test 
were written with dhclient originally and worked fined with that.

But you might know ISC dhcp client is deprecated and unsupported. There 
is a nice alternative still supported, dhcpcd. But it requires on 
difference and that is presence of Router Advertisement Managed flag set.

dnsmasq has support for --enable-ra to send exactly such advertisements, 
which will then dhcpcd use to query DHCP server. The problem I see is it 
requires configured --dhcp-range for the network.

But using --dhcp-relay and --dhcp-range do not make sense on the same 
network, right? Unfortunately dhcpcd just won't even try to send DHCP 
request to multicast address, until it has indication from the network 
it should try it.

I think it would make sense to extend --enable-ra to send RA also from 
local addresses specified by --dhcp-relay address. Or at least have it 
explicitly enabled by --ra-param=<device>. The similar problem seems to 
have --dhcp-range=::,static. That won't be used by dhcpcd also, because 
it did not match correct network.

Would be patches implementing this desired? Do you know any different 
option, how to test dnsmasq --dhcp-relay with dhcpcd?

Cheers,
Petr

-- 
Petr Menšík
Senior Software Engieer, RHEL
Red Hat, https://www.redhat.com/
PGP: DFCF908DB7C87E8E529925BC4931CA5B6C9FC5CB