In the begining we have to install a DHCP relay agent; Which I use (dhcp-helper) but there is another package called dhcp3-relay.
Dhcp-helper is much smaller than dhcp3-relay package and it does not require the Packet Filter kernel facility to be present. This makes it a good choice for use on small or embedded systems. Unlike dhcp3-relay, dhcp-helper can be configured to forward DHCP requests as broadcasts, and therefore does not need to be given the IP address of the DHCP server, only the network in which it resides.
#apt-get install dhcp-helper/etc/default/dhcp-helper
DHCPHELPER_OPT=“-i eth0 -b eth1”Here eth1 is the interface that connects to the dhcp server and eth0 is the interface that receives broadcast messages. We specified that the broadcast messages wich received by eth0 will be published on eth1.
In below, we specify that the messages should be sent to the dhcp server as unicast:
DHCPHELPER_OPS=“-i eth0 -s [IP Server]”