Configuration of DHCP in Linux

DHCP Server Configuration

 In DHCP server the IP addresses are automatically assigned to the clients and these IP addresses are known as Dynamic IP addresses

Service Profile

Package:dhcp

Server Daemon:dhcpd

Client Daemon:dhclient

Configuration File:/etc/dhcpd.conf

Port:67,68

 Set the system ip statically

IP: 192.168.0.254
NetMask: 255.255.255.0
Gateway: 192.168.0.254
[root@server~]# service network restart
[root@server~]#  chkconfig network on

 [root@server~]# yum install dhcp* -y
[root@server~]#  cp /usr/share/doc/dhcp-3.0.5/dhcpd.conf. Sample  /etc/dhcpd.conf
[root@server~]#  /etc/dhcpd.conf

     subnet 192.168.0.0 netmask 255.255.255.0 {     #Network ID
     option routers 192.168.0.254;                             #Gateway or router IP
     option subnet-mask 255.255.255.0;
     option nis-domain "HIT.com";                              #NIS Domain
     option domain-name "HIT.com";                          #DNS Domain
     option domain-name-servers 182.2168.0.1;        #DNS IP

    option time-offset -18000; # Eastern Standard Time
# option ntp-servers 192.168.1.1;
option ntp-servers 172.24.0.254;
# option netbios-name-servers 192.168.1.1;
option netbios-name-servers 172.24.0.254;     range dynamic-bootp 192.168.0.1 192.168.0.50;
        default-lease-time 21600;

        max-lease-time 43200;

   # we want the nameserver to appear at a fixed address

host ns {
                    hardware ethernet aa:ab:56:78:AB:CD;       #MAC Address

                    fixed-address 192.168.0.30;               

 }
   host nfs {                                                             #reservation of IP
                 option host-name server1.HIT.com;
                 hardware ethernet aa:ab:56:78:AB:CD;                 #MAC Address
                 fixed-address 192.24.0.15;
}
}

:wq

[root@server~]#  service dhcpd restart
[root@server~]# chkconfig dhcpd on

Client Side configuration

Method1

 To get IP from DHCP use netconfig command

[root@client~]#netconfig

Select

[*]Use dynamic IP configuration(BOOTP/DHCP)

[root@client~]#service network restart

[root@client~]#ifconfig

Method2

 [root@client~]#dhclient  -r  # -r for release

[root@client~]#dhclient

[root@client~]#ifconfig

 

Note:Remove the HOSTNAME entry from /etc/sysconfig/network file in order to get the ip from DHCP server otherwise this name will overridden whcich is coming from DHCP server

[root@client~]# vi /etc/sysconfig/network

NETWORKING=yes

:wq!