How to configure DHCP Server on Ubuntu

To configure DHCP Server on Ubuntu

DHCP stands for Dynamic Host Configuration Protocol which can used to allocate dynamic IP address for Client Systems. Dynamic IP’ s are automatically request from dhcp server, where static IP’ s are manually configured by user or system administrator. In order to simplify the work for administrator DHCP can be used to allocate IP address automatically for N number of systems.

To configure DHCP Server

In order to configure DHCP, you should update your repositories. Use the following command for the same process.

root@linuxhelp:~# apt-get update
Hit:1 http://security.ubuntu.com/ubuntu xenial-security InRelease
Hit:2 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial InRelease 
Hit:3 http://in.archive.ubuntu.com/ubuntu xenial InRelease              
Hit:4 http://in.archive.ubuntu.com/ubuntu xenial-updates InRelease
Hit:5 http://in.archive.ubuntu.com/ubuntu xenial-backports InRelease
Reading package lists... Done

Use the following command to install the package for DHCP Server

root@linuxhelp:~# apt-get install isc-dhcp-server -y
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-4.4.0-42 linux-headers-4.4.0-42-generic linux-headers-4.4.0-53 linux-headers-4.4.0-53-generic linux-image-4.4.0-42-generic linux-image-4.4.0-53-generic
  linux-image-extra-4.4.0-42-generic linux-image-extra-4.4.0-53-generic
Use ' sudo apt autoremove'  to remove them.
The following additional packages will be installed:
  libirs-export141 libisccfg-export140
Suggested packages:
  isc-dhcp-server-ldap policycoreutils
.
.
.
Setting up libisccfg-export140 (1:9.10.3.dfsg.P4-8ubuntu1.4) ...
Setting up libirs-export141 (1:9.10.3.dfsg.P4-8ubuntu1.4) ...
Setting up isc-dhcp-server (4.3.3-5ubuntu12.6) ...
Generating /etc/default/isc-dhcp-server...
Processing triggers for libc-bin (2.23-0ubuntu3) ...
Processing triggers for systemd (229-4ubuntu10) ...
Processing triggers for ureadahead (0.100.0-19) ...

Now, assign the network interface with the help of following command.

root@linuxhelp:~# vim /etc/default/isc-dhcp-server
INTERFACES=” ens33” 
To configure DHCP service we need to edit dhcpd.conf file and mention the following required values in your configuration
Network IP : 192.168.7.0/24
IP Range : 192.168.7.141 - 192.168.7.145
Gateway : 192.168.7.1
Primary DNS : 192.168.7.130
Sec DNS : 8.8.8.8

root@linuxhelp:~# vim /etc/dhcp/dhcpd.conf
subnet 192.168.7.0 netmask 255.255.255.0
{
    range 192.168.7.141 192.168.7.145 
    option domain-name-servers 192.168.7.130, 8.8.8.8 
    option domain-name " linuxhelp.example.com"   
    option routers 192.168.7.1 
    option broadcast-address 192.168.7.255  #Broadcast
    default-lease-time 600 
    max-lease-time 7200 
}

Once the DHCP configuration is done, start and enable the service to take effect.

root@linuxhelp:~# systemctl start isc-dhcp-server6
root@linuxhelp:~# systemctl enable isc-dhcp-server6

Now DHCP server is setup and ready.