Simon Hobson dhcp1 at
Mon Oct 6 07:10:19 UTC 2014

Ellad G. Yatsko <eyatsko at> wrote:

> Maybe this question have already "set your teeth on edge". :-) But...
> I wonder how to set up ISC DHCPD to be Cisco VRF aware when
> IP Pools are overlapped.
> For example:
> VRF_A has    and
> VRF_B has
> I know all about option 82, but I can't use it because ISC DCHP doesn't
> allow to introduce in its configuration neither overlapped subnets nor
> overlapped pools.

Unfortunately for you, the ISC server doesn't support blatantly broken IP networks. <soapbox>Any network using other than globally unique addresses and non-overlapping subnets is by definition broken.</soapbox>

But ...
What you could do is run two (or more) separate dhcpd instances (one per VRF) with separate config files. You'll need to roll your own startup scripts as the standard scrips provided by distributions only handle a single instance.
Each instance will need to run on it's own interface - and I'm not certain if these can be VLAN interfaces or if they need to be physically separate NICs.

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