client took a host assigned ip

Simon Hobson dhcp1 at
Sat Feb 24 00:13:11 UTC 2007

anthony wrote:

>I have a mac os client that for some reason requested an ip that was not
>in dhcp range but rather was a host assigned ip.
>The logs show the dhcp server never offered the ip to that mac os.
>How do I ensure not no clients get host assigned ip's.

It is sufficient (with the ISC server) to not include the address in 
a range or a fixed-address statement, it will then NOT be offered to 
any client.

The server will not however NACK an address that a client might 
request if the address is a valid address for the subnet - eg in the 
example config you give, would be considered valid (and 
not NACKed) but would NOT be offered to a client. So if you have 
another dhcp server on the subnet then it is quite easy for the other 
server to hand out addresses you did not intend to be used.

Another explanation is that a client has moved from another network 
and is requesting the address it last had.

>Do I need to   make a pool of host assigned ip's and deny the clients
>like this?
>         pool {
>                  failover peer "dhcp-failover";
>                  range;
>                  range;
>                  option domain-name-servers;
>                  deny dynamic bootp clients;
>          }
>          pool {
>                  range;
>                  deny all clients;
>          }
>host procurve2wp {
>          hardware ethernet 00:08:83:FF:FA:80;
>          fixed-address;

No, there is no need for that.

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