How to not allocate any address to a specific host?

[Simon Hobson]

David Landgren wrote:

>class "obsolete-hosts" {
>      match pick-first-value (option dhcp-client-identifier, hardware);
>}
>
># i000003492
>subclass "obsolete-hosts" 00:0a:e4:36:7b:4b;
>
>shared-network example-net {
>
>      subnet 172.17.0.0 netmask 255.255.224.0 {
>          range               172.17.16.0 172.17.17.255;
>          option ntp-servers  172.17.0.8;
>          option time-servers 172.17.0.8;
>          option routers      172.17.0.6;
>
>          option domain-name          "example.com";
>          option domain-name-servers  172.17.0.8, 172.17.0.18;
>          option netbios-node-type    2;
>          option netbios-name-servers 172.17.0.8;
>
>          default-lease-time  86400; #  1 days
>          max-lease-time     864000; # 10 days
>      }
>
>      subnet 10.2.0.0 netmask 255.255.255.252 {
>          pool {
>              allow members of "obsolete-hosts";
>              deny unknown-clients;
>
>              default-lease-time  15;
>              max-lease-time      10;
>              range 10.2.0.0 10.2.0.3;
>          }
>      }
>}



>So, what am I missing here?

You don't have the right allow/deny statements.

Firstly, there is nothing to deny obsolete-hosts from the 172.17 
subnet. So in here you want "deny members of "obsolete-hosts"".

Secondly, you have mixed allow & deny in the 10.2 subnet. I believe 
this does NOT work as you might expect. Having "allow members of 
"obsolete-hosts"" is sufficient to deny anything NOT in that class.

What is probably happening is that a client with a 172.17 address is 
added to the obsolete-hosts class, but because it isn't denied from 
having an address in that subnet, it can carry on leasing that 
address.

So you probably want something like :

shared-network example-net {

      subnet 172.17.0.0 netmask 255.255.224.0 {
          other stuff
          pool {
              deny members of "obsolete-hosts";
              range               172.17.16.0 172.17.17.255;
          }
      }

      subnet 10.2.0.0 netmask 255.255.255.252 {
          default-lease-time  15;
          max-lease-time      10;
          pool {
              allow members of "obsolete-hosts";
              range 10.2.0.0 10.2.0.3;
          }
      }
}


Simon