LinuxQuestions.org - dhcpd inconsistent behavior

First of all, this is not urgent since dhcp works just fine, but I was wondering why this happens:

I have two subnets configured in dhcpd.conf
One of them handles range 1-239 and assigns fixed IPs based on mac addresses. e.g.:

Code:

host computer

{

    hardware ethernet 00:11:22:33:44:55;

    fixed-address 123.456.789.10;

}

Second handles the rest (240-254) and assigns a dynamic IPs from the range to defined hosts. e.g.:

Code:

host another-computer { hardware ethernet 55:44:33:22:11:00; }

The first subnet automatically ignores all computers not listed as hosts.

The second subnet required a

Code:

boot-unknown-clients false;

to behave the same way, otherwise it just assigns an address from the range to everyone.

Code:

authoritative;

is in global options.

Any ideas?
Thanks.