2 Replies Latest reply on Apr 27, 2012 11:09 AM by zprime

    DHCP reservations  and exclusions

    zprime New Member

      This is part question, part feature request.


      I normally set aside a block of 100 addresses (from a /24) in DHCP, and I use exclusions to keep the pool from handing out the rest.


      However, now I want to put some network equipment (managed switches) down in the range below .100.  Best practices suggest using DHCP reservations for those hosts, because then if a change needs to be made to default gateway, DNS, or other settings, the reservation just needs to be updated for that hardware rather than having to login to the equipment itself to change it (as would be the case with a hard-set static IP).


      From what I can tell, if I have .1-.99 excluded, DHCP won't hand out a reserved IP that lies within that block (.3 for example).  This is counter-intuitive to me, and it's actually the opposite of Microsoft DHCP.  I would expect the exclusions to apply to the "pool", but if I setup an individual IP reservation, I expect the exclusions to be ignored and for DHCP to simply give that IP to that device.


      Am I correct in the understanding that the exclusions are preventing DHCP from issuing a single address to a reserved host?  Is there any chance this could be changed in a future release so reservations aren't affected by pool exclusions?

        • Re: DHCP reservations  and exclusions

          @zprime - Thanks for posting your question on the forum. You are correct in your statement. The fact that those IP addresses have been excluded prevent them from being handed out by the DHCP server, even to reserved hosts. I can most certainly put in a feature request for what you are asking. However, I cannot say if or when the change would be made.


          Please let us know if you have any further questions.




            • Re: DHCP reservations  and exclusions
              zprime New Member

              Please do submit the feature request, it seems like a logical thing to me and I'm surprised that it works the way it does right now.  In the mean time I can work around it by editing my exclusions or just using static addresses, but it's mildly annoying.