Configuration problem

Randall C Grimshaw rgrimsha at
Sun May 3 13:05:34 UTC 2009

If I read your description correctly, your host declaration is an address that the host is not permitted to use. A sort of deny.

In this case I suspect, if I read your description correctly, you will need a second host declaration without a fixed address that will allow it to be given a dynamic address from the allowed pool.

We also see this where a fixed decalaration is made in one subnet and the machine is moved to another. It requires two host declarations - one fixed and one not fixed.

An odd behavior, but one we have become accustomed to.


From: dhcp-users-bounces at [dhcp-users-bounces at] On Behalf Of MickB [mickb at]
Sent: Sunday, May 03, 2009 7:41 AM
To: dhcp-users at
Subject: Configuration problem


I post on this mailing-list because I encounter a configuration problem
of my DHCP server. After many tests and careful read of the man pages, I
didn't succeed to solve it. I even suspect a bug.

Configuration used:
    * Linux
    * Glibc 2.8
    * DHCPd v4.1.0

Here's some explanations.
I have a single subnet: I have declared two clients classes:
    - one for clients which MAC address begins by 00:FF,
    - one for clients which MAC address doesn't begin by 00:FF.

- In the first class, clients get an IP in the pool -, and get a router address
- In the second class, clients get an IP in the pool -, and no router address

For this purpose, this DHCP server configuration is working correctly:

### Classes ###
class "test" {
        match if substring (hardware, 1, 2) = 00:FF;

### Subnets ###
subnet netmask {

        pool {
                deny members of "test";
                option routers;

        pool {
                allow members of "test";

        option subnet-mask;
        option broadcast-address;


However, it doesn't work anymore when I had a host declaration with a
fixed-address like this:

host toto {
        hardware ethernet 00:12:A8:13:E1:40;

In such case, the host "toto" doesn't get the router address. I believe
it isn't coherent. Host "toto" doesn't belong to the "test" class, so
the first pool in the subnet should match. The range is only for the
case of dynamic address allocation and is no use in this case. But
"option routers" should be taken into account, no ?

Any help would be appreciated :)


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