DHCPv6 and RA

Simon Hobson dhcp1 at thehobsons.co.uk
Thu Dec 10 17:08:20 UTC 2020


Usman Ahmad <usman.hfd at gmail.com> wrote:

> 1- DHCPD6.CONF doesn't have any option to mention a gateway for DHCP6 clients. Note that i need to configure multiple subnet6 so the gateway for each subnet will be different. 
> 2- I have tried to include external configuration files to dhcpd6.conf using attribute include but it isn't accepting.  


As Steinar says, DHCP (as well as the rest of address management)works somewhat differently in the IPv6 world to how it works in the IPv4 world.

Information on the subnets (called prefixes in the IPv6 world) that are on the network segment come via RA announcements from the router(s) attached to that segment. Each router will send RAs which list the prefixes in use, whether they are considered "on list", and how addresses are assigned. You need to specifically set one or more flags (and TBH I can't remember the combination needed) in an RA to signal to a host that it should use DHCP - otherwise IIRC the default is that the host will not use DHCP at all.
And note that Android devices don't support DHCPv6 at all as a matter of policy from Google.

Simon



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