Multiple subnets on one Interface

Simon Hobson dhcp1 at
Mon Jan 27 22:15:19 UTC 2014

Steve Clark <sclark at> wrote:

> How will dhcpd give out ips? Will it alternate? Give all of one subnet then start the other
> subnet?

The official answer is that it is not determinate - as in you cannot in any way rely on any specific allocation order.

The practical answer is that *currently* the implementation dependent order is that it will allocate unused addresses starting with the numerically highest and working down - I believe this is due to the way the internal hashing tables work. This is implementation dependent, not officially documented, and liable to change at any time without warning - if you want a specific allocation strategy then you will need to explicitly define it in the config.

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