Dear Friend ,

I have a DHCP server where 13 real IP are used .I have configured properly and it works fine ? I have 10 clients agains this DHCP server .

But after 3/4 month i get a problem . My Clients pc cannot get IP from DHCP server several times . Then if I set IP statically then they get internet . But I cannot understand why sometimes my client pc can't get IP from DHCP server ?

Waiting for ur help ..........

I'm not sure I understand you correctly, but if you mean that your DHCP server has 13 addresses it can lease, this may not be enough if your lease time is long. In some cases, the DHCP server will lease an IP to a computer, the computer will shut down or crash unexpectedly, and then the DHCP server will give it another without releasing the first one. While the DHCP server is supposed to be smart enough to release the address automatically when a computer requests another, misconfigured servers can keep the address reserved, thus running you out of IPs to assign.

If you meant that there are 13 statically assigned IPs on the same network, make sure the DHCP server is not allowed to lease those same IPs, as this would result in an IP conflict.

It is also possible that if you are on a large network, but in your own subnet, that some clients outside your subnet are mistakenly recieving addresses from your DHCP server. This would only apply on larger networks like those in schools or corporations, and would require configuration on the routers between the subnets.


As a real solution, I'd recommend either revising the lease policy on the DHCP server or adding more IPs available to lease.

Dear cs.craker ,

Thx for ur reply . My Ip block for DHCP server is "202.59.125.20/28".Domain (Let , example.com) My "/etc/dhcpd.conf" file is the following :

ddns-update-style interim;
ignore client-updates;

subnet 202.59.125.0 netmask 255.255.255.0 {

# --- default gateway
option routers 202.59.125.20;
option subnet-mask 255.255.255.240;

option nis-domain "domain.org";
option domain-name "example.com";
option domain-name-servers 202.59.136.2;

option time-offset -18000; # Eastern Standard Time
# option ntp-servers 192.168.1.1;
# option netbios-name-servers 192.168.1.1;
# --- Selects point-to-point node (default is hybrid). Don't change this unless
# -- you understand Netbios very well
# option netbios-node-type 2;

range dynamic-bootp 202.59.125.21 202.59.125.34;
default-lease-time 21600;
max-lease-time 43200;

# we want the nameserver to appear at a fixed address
host ns {
next-server marvin.redhat.com;
hardware ethernet 12:34:56:78:AB:CD;
fixed-address 207.175.42.254;
}
}

My DHCP server has 3 Lan card and has 3 different Network . My IP Block for DHCP is 202.59.125.20/28. In this Configuration My DHCP server has 10/11 Clients . But now the problem is My clients are not get IP dynamically from My
DHCP server . So that they use their IP Statically . In this situation what is the solution of my problem . Is the problem occured for "default-lease-time" or others ? Plz help me again ...