isc-dhcpd offers ip already reserved

Simon Hobson dhcp1 at
Thu Jun 5 09:54:00 UTC 2014

IT Support <it.compilation at> wrote:

> Yes I do, is it wrong this kind of setting?

Yes, as Glen says, defining a static assignment does not "reserve" the address out of any dynamic pools it may be in. This is a common issue with admins used to the Microsoft way of doing things. The ISC server does have an equivalent of the Microsoft way - you can "reserve" a lease to a specific client by adding the flag "reserved;" to the lease record - you either have to stop the server and edit the leases file, or use OMSHELL, to do this.

> This setting that I'm using is because of in the past I was getting a lot of ip conflicts between users asking to the dhcp server for a idle ip address, and a way to solve it, was give it to them fixed ip addres just for few to whom was getting  ip addres conflict.

You need to look at what problem was causing this. If a client asks for an address, it should not be given one that is in use - provided the server is properly configured. There are however some client config issues that can cause problems.

> I'd like to find a work around for this issue.

Which one ? The one you asked about (which has been answered - don't have an address that is both in a dynamic range and a static assignment) or the one that is causing the underlying problem ?

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