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Old 05-07-2008, 06:15 AM   #1
Registered: Jan 2006
Posts: 112

Rep: Reputation: 15
dhcpd assigning reserved mac-to-ip addresses to unregistered pcs

Dear Sir/madam

i set up dhcpd recently to only assign ip addresses to only know mac addresses. the range is also setup so there are enough ip addresses to be given out to all the mac-to-ip reservations and know more.
My problem is that if i add an unknow laptop whos mac addresses have not been recored the dhcpd server still assigns it an ip address(an ip address which is already reserved for another known mac addres pc). I did this setup in the first place to control the computer which connect to my basic network.
my dhcpd.conf file is below. if anyone can shed some light on this i would be most greatful....

# DHCP Configuration file for subnet 138.37.65 updated 12.10.2003
# DNS update scheme

ddns-update-style interim;

# Subnet declaration

subnet netmask {
option routers;
option subnet-mask;

option domain-name "";
option domain-name-servers;


# MAC address to IP mapping

host copeedddl {
hardware ethernet 00:0d:54:a8:90:85;

host akroasdku {
hardware ethernet 00:08:74:46:89:db;

host NP15F3B33EC {
hardware ethernet 00:01:e6:5f:3b:ec;

host lpt106aa {
hardware ethernet 00:06:5b:02:bd:67;

# Range Parameter

default-lease-time 600;
max-lease-time 86400;
[root@zika etc]#
Old 05-07-2008, 09:02 AM   #2
Registered: Feb 2008
Location: JHB South Africa
Distribution: Centos, Kubuntu, Cross LFS, OpenSolaris
Posts: 806

Rep: Reputation: 41
You need the option ignore unknown-clients
Old 05-07-2008, 01:48 PM   #3
LQ Guru
Registered: Nov 2004
Location: Saint Amant, Acadiana
Distribution: Gentoo ~arch
Posts: 6,147

Rep: Reputation: Disabled
You are using public addresses, I assume you do not do NAT. Are you sure there is no other DHCP server and your computers are actually using your DHCP server?
Old 05-08-2008, 05:39 AM   #4
Registered: Jan 2006
Posts: 112

Original Poster
Rep: Reputation: 15
Talking i think it works

cheers for replies
i think the ignore unknown-clients option has done the job. IP addresses were still been given out to any unknown pc(not using nat). But now it seems to be under control- pcs seem to get a limited connectivity response or in the case of wireless in a continuous loop in tring to obtain ip.
thanks very much. Now just left to edit the iptables to prevent somebody being smart and trying to use static ip to get connected. hope its going to be more straight forward..


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