DHCP server only works one time

Question

I installed e configured the DHCP server and removed all network-manager*.

All my settings are just like this one: dhcpd fails to start on eth1 (but i use eth0)

I do:

sudo ifdown eth0
sudo ifup eth0

Then plug the cable between the server and the client. The client receives the correct IP address: 192-168.0.50

BUT, if I unplug the cable and put it back the Client doesn't receive a valid IP address. I have to make sudo ifdown eth0, sudo ifup eth0 at the server to the client receive a valid IP address again.

How do I fix this?

EDIT: my current configuration files are:

$ cat /etc/default/isc-dhcp-server
INTERFACES="eth0"

,

$ cat /etc/dhcp/dhcpd.conf
ddns-update-style none;

default-lease-time 600;
max-lease-time 7200;

subnet 192.168.0.0 netmask 255.255.255.0 {
  interface eth0;
  range 192.168.0.50 192.168.0.100;
  option subnet-mask 255.255.255.0;
  option broadcast-address 192.168.0.255;
  option routers 192.168.0.1;
}

,

$ cat /etc/network/interfaces
auto eth0
iface eth0 inet static
address 192.168.0.1
network 192.168.0.0
netmask 255.255.255.0
broadcast   192.168.0.255
#gateway    192.168.0.1

,

$ cat /etc/resolv.conf
nameserver 192.168.0.1

I'm not using any router or switch. Just two PCs connected my cable. After rebooting the server, i have to

$ sudo isc-dhcp-server start

After this the client PC obtains a correct IP. BUT if I unplug the cable and connect it again, it won't get an IP in the correct range. I have to ifdown and then ifup eth0.

Answer 1

If you removed or disabled NetworkManager you need to configure networking manually.

1) Add your nameserver in /etc/resolv.conf

# change '192.168.0.1' to the nameserver you want to use.
nameserver 192.168.0.1

2) Bring your network down.

sudo service networking stop

3) Edit /etc/network/interfaces

# command line
sudo -e /etc/network/interfaces

# graphical
gksu gedit /etc/network/interfaces

Add in your configuration for eth0. With DHCP it is short.

auto eth0
iface eth0 inet dhcp

4) Bring your network up

sudo service networking start

dhcp / networking should then work properly when you re-boot.