How to config dhcpv6 server to assign multiple subnet address

David W. Hankins dhankins at
Fri Mar 19 00:02:51 UTC 2010

On Fri, Mar 12, 2010 at 11:24:41AM +0800, shirley zhou wrote:
> I want to config dhcpv6 server to assign two subnet address.


	limit-addrs-per-ia 2;

To the config file.

It is a little lame because what it actually does is it tries to
give 'n' addresses starting from the first valid pool in a shared
network.  So if you have two pools in one subnet, it will try to
give two addresses from those two pools I think.

This is exacerbated by a strangeness in our configuration system,
which is that we prefer to have IPv6 pools delimited by prefix,
rather than by range.  So ::10 to ::20 doesn't land directly on
powers-of-two boundaries, and the server manufactures multiple
pools to cover the range.

I would suggest using a;

    range6 3ffe:501:ffff:104::100/120;

Or similar to ensure the range is a specific single power-of-two
prefix length.

> My config file as following:
> The global address of dhcp server is : 3ffe:501:ffff:104::XX
> #cat /root/dhcp6s.conf
> subnet6 3ffe:501:ffff:104::0/64 {
> range6 3ffe:501:ffff:104::10 3ffe:501:ffff:104::20;
> }
> subnet6 3ffe:501:ffff:103::0/64 {
> range6 3ffe:501:ffff:103::10 3ffe:501:ffff:103::20;
> }

If these subnets are on the same broadcast domain, you need to
enclose them in a shared-network {} statement so that the server
knows this and can allocate them appropriately.

I'm not sure this feature is well exercised in the DHCPv6 server in
operation, so please report back if you get it to work. :)

David W. Hankins	BIND 10 needs more DHCP voices.
Software Engineer		There just aren't enough in our heads.
Internet Systems Consortium, Inc.
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