- DHCP stands for Dynamic Host Configuration Protocol, One of the basic element found on all networks is a DHCP Server, making it an important part of any network.
- DHCP makes Network Administration easy because you can make changes to a single point on your network and let those changes filter down to the rest of the network.
DHCP follows the
” DORA
“ process, DORA means
D – Discover
O – Offer
R – Request
A – ACK
Boot P Server:
In
this method the Administrator used to collect the MAC Address to them. The list
of MAC Address and IP Address was maintained in a Server called as a Boot P Server. When ever client request
for IP Address Boot P Server assign
the IP. In this method the
Administrator used to collect the MAC Address.
DHCP:
- It gives IP – Address automatically to the clients who is requesting for an IP Address.
- It provides centralized IP-Address management.
- DHCP reduces the complexity and amount of administrative work by assigning TCP/IP configuration.
Steps to Install
Configuration:
Step1: Start by installing the dhcp Package
#yum –y install dhcp
Step2: Verify that
the package is installed correctly
# rpm –qa / grep dhcp
Step3: Make sure that
the dhcpd service starts when the system boots as well
# chkconfig dhcpd on
Step4: Verify that
the DHCP service starts on boot
# chkconfig dhcpd --list
Step 5: Edit
/etc/sysconfig/dhcpd file
Firstly we
need to set ethernet interface name as DHCPDARGS in /etc/sysconfig/dhcpd file.
Edit this configuration file and update the ethernet name.
DHCPDARGS=eth0
Step6: DHCP
Configuration
To start the
configuration, let’s look at the important files that handle the options for
the DHCP services:
/etc/dhcp/dhcpd.conf : Main
Config file for the DHCP Service.
/var/lib/dhcpd/dhcpd.leases : IPV4 client lease file
DHCP creates an
empty configuration file /etc/dhcp/dhcpd.conf. Also it provides a sample
configuration file at /usr/share/doc/dhcp*/dhcpd.conf.sample. To Copy the Sample file, use the following
command.
# cp /usr/share/doc/dhcp-4.1.1/dhcpd.conf.sample /etc/dhcp/dhcpd.conf
Step 6.1 : Parameter
& IP Subnet Declaration
Open the main Configuration
file in vi editor, and change the configuration like below
# vim /etc/dhcp/dhcpd.conf
In this example we
are configuring DHCP for 192.168.0.1/24 LAN network.
subnet 192.168.1.0 netmask 255.255.255.0 {
option routers 192.168.1.1;
option subnet-mask 255.255.255.0;
option domain-name "bsrtech.net";
option domain-name-servers 192.168.1.254;
default-lease-time 21600;
max-lease-time 43200;
#Client IP range
range dynamic-bootp 192.168.1.2 192.168.1.100;
}
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:wq! (save&quit)
Step6.2: Check the
config file for any errors
# service dhcpd configtest
Step6.3: Assign
Static IP-Address to host
Assigning IP-Address dynamically has
some problem that every time a client system boots it is not sure that it will
get the same IP, So it will be tedious task for other systems to find the
particular system. To solve the above problem we can do MAC address binding of
the IP address for this provide its entity in the fixed address portion.
Open the Main Config file :
# vim
/etc/dhcpd/dhcpd.conf
Host client1 {
Option host-name “client1.example.com”;
Hardware Ethernet 03:C6:7C:45:GG:RR;
Fixed-address 192.168.1.20;
}
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Step7 : Restart the
DHCP service
# service dhcpd restart (or)
# /etc/init.d/dhcpd restart
Step8 : Linux Client
side Configuration
Client configuration
is very easy and straightforward. All you need to do is set IP address to
dynamic in the properties of lan card.
# vim /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=dhcp
TYPE=Ethernet
ONBOOT=yes
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Make sure BOOTPROTO is set to dhcp.
Now restart the network services in client system, Dynamic
IP address is assigned to ur System.
# service network restart
Step9 : Windows
Client Configuration
To configure windows system as dhcp clients open lan card
properties and select tcp/ip and click on properties and set obtain an ip
address automatically.
thanks brother
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