[Dnsmasq-discuss] 6in4, dhcp srv still offers IPv4. is lan still needed?

[Roy Marples]

On 2014-09-22 19:48, glphvgacs wrote:
> hello,
> i posted a earlier version fo this on openwrt-users list with some
> interesting responds. here is the tip of the thread just in case:
> https://lists.openwrt.org/pipermail/openwrt-users/2014-September/003139.html

> ------------------/etc/dnsmasq.conf:
> -------------BEGINS-----------------
> log-queries
> log-dhcp
> #cache-size=512
> cache-size=1024
> # i have used ,static here which resulted in no IPv6 being offered at 
> all
> # i tested earlier with (note 'static')
> # dhcp-range=2001:470:1f07:12d::,static
> # which resulted in no IPv6 being offered at all
> dhcp-range=2001:470:1f07:12d::,ra-names
> enable-ra
> ------------------/etc/dnsmasq.conf:
> -------------ENDS-------------------
> 
> client side log of DHCP negotiations for ethernet on my_machine:
> 
> dhcpcd[29585]: enp3s0: carrier acquired
> dhcpcd[29585]: enp3s0: IAID 41:38:18:b0
> dhcpcd[29585]: enp3s0: soliciting an IPv6 router
> dhcpcd[29585]: enp3s0: Router Advertisement from fe80:::
> dhcpcd[29585]: enp3s0: adding address 
> 2001:***:***7:***:****:****:****:****/64
> dhcpcd[29585]: enp3s0: adding route to 2001:***:***:***::/64
> dhcpcd[29585]: enp3s0: adding default route via 
> fe80::6a7f:74ff:fe30:f2e2
> dhcpcd[29585]: enp3s0: rebinding lease of 192.168.1.222
> dhcpcd[29585]: enp3s0: leased 192.168.1.222 for 43200 seconds
> dhcpcd[29585]: enp3s0: adding route to 192.168.1.0/24
> dhcpcd[29585]: enp3s0: adding default route via 192.168.1.1
> dhcpcd[29585]: enp3s0: Router Advertisement from fe80:::
> 
> 
> now what i would like to happend is for dnsmasq to stop offering IPv4.
> i.e. do dhcpv6 but no traditional dhcp.  in other words a pure IPv6 
> network
> with no IPv4 offered, something like this:
> http://www.rfc-editor.org/rfc/rfc6586.txt

Maybe something in OpenWRT is giving dnsmasq a different config file or 
appending to it?
Check the running processes for the commandline launching dnsmasq for 
clues.

 From a DHCP perspective, you may wish to enable RFC2563
https://www.rfc-editor.org/rfc/rfc2563.txt
This effectively allows a DHCPv4 transaction, but no IP address is sent 
to be leased AND a magic bit is sent instructing the client not to 
attempt IPv4LL.
Without this, dhcpcd which you use, in it's default state will assign an 
IPv4LL address due to the lack of a DHCP one.

I don't know of any other DHCP client which supports this, so YMMV.

Thanks

Roy