1. Mr. NHEAN Sophan sophan.nhean@gmail.com Page 2
DHCP Server and DHCP Relay Agent Network Infrastructure
 DHCP Server: Computer or computers which function as server(s) provide network
configurations automatically to clients such as IP Address, subnet mask, default
gateway, domain name, DNS server, etc.
 DHCP Relay Agent: The DHCP Relay Agent (dhcrelay) allows for the relay of DHCP
and BOOTP request from a subnet with no DHCP Server on it to one or more DHCP
servers on other subnets. When a DHCP client requests information, the DHCP Relay
Agent forwards the request to the list of DHCP servers specified when the DHCP
Relay Agent is started. When a DHCP server returns a reply, the reply is broadcast
or unicast on the network that sent the original request.

2. Mr. NHEAN Sophan sophan.nhean@gmail.com Page 3
I. Configuring DHCP Server
1. Install DHCP Server by using dhcp-3.0.5-18.el5.i386.rpm
2. Copy the sample of DHCP Configuration file from /usr/share/doc/dhcp-
3.0.5/dhcpd.conf.sample
3. Go to edit the configuration file by vim /etc/dhcpd.conf
4. DHCP Server provides a scope of IP Address in Subnet 192.168.2.0, Net mask
255.255.255.0 (Range: 192.168.2.10 – 192.168.2.254) and provides the fixed address
for Manager.

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5. Go to /etc/sysconfig/dhcpd
6. Configure interface for DHCP Server to listen the request from clients.
7. Start or Restart the service DHCP Service.
8. Configure DHCP Service to start automatically
9. Stop the firewall service

4. Mr. NHEAN Sophan sophan.nhean@gmail.com Page 5
II. Configuring DHCP Relay Agent
1. Install DHCP Server by using dhcp-3.0.5-18.el5.i386.rpm
2. Go to DHCP Relay Agent configuration file by vim /etc/sysconfig/dhcrelay
3. Configure interfaces relay from client LAN and DHCP Server (eth0 and eth1) and
DHCP Server’s IP Address (192.168.1.2)
4. Start or Restart DHCP Relay Agent service (dhcrelay)
5. Configure DHCP Relay Agent (dhcrelay) service to start automatically.
6. Set the configuration from 0 to 1 to enable the router, forwarder option.

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III. Testing DHCP Server
1. Client Manager, he got the reservation IP address
2. And other clients got other IP Addresses, and so on.
The End!