Thank You for Your time and answer, Johannes:
>What's your /etc/network/interfaces ?
>Is there any hotplugging happening?
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
#allow-hotplug eth0
iface eth0 inet static
address 192.168.0.100
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255