In this tutorial, we learn about the Linux DHCP Server step by step. As we all know, every computer requires an IP address to connect to the network, In small networks, it is not a problem to assign manually IP address to every computer,
but when working with tens or hundreds of network devices, one has to be very careful, in order not to make mistakes. To make things easier, we could delegate this task to the DHCP server.
What DHCP does is essentially provide IP addresses to all network devices. In fact, not only can it provide IP addresses, but also parameters, such as default gateway, DNS server, etc.
How DHCP Server Works
when the DHCP client boots up, it sends a DHCP to discover a message to all the network-connected machines. By this means, it tries to find an available DHCP server.
If there are one (or more) DHCP servers in the network, it will answer back with a DHCP offer message. When the client receives one of these DHCP offer messages,
it will send back a DHCP request to the server. The server, in turn, replies with a DHCP acknowledge message, and the address is assigned.
Bellow Image Explain About the DORA ( Discover, Offer, Request, Acknowledge)
Check IP Address in DHCP Server
First, provide a Static IP address to the DHCP server. Check Static IP Address in your computer follow bellow Image. we have set 192.168.43.74 IP in DHCP server
Install DHCP Package:
Before installing the package of the DHCP server, check the status of the DHCP package in the system. You can check the package with the help of below-given command.
[root@simi ~ ]# dnf list --installed |grep dhcp-server
If DHCP package is not installed in your system then now you have to install DHCP package
dnf install dhcp-server
After successfully installing the DHCP package on your server. Now you open the DHCP server main configuration file /etc/dhcp/dhcpd.conf file remains empty, Now we can write the configuration code of dhcp in the file or overwrite the file form.
The easiest way to configure a new DHCP server is probably to overwrite the default (empty) configuration file with /usr/share/doc/dhcp-server/dhcp.conf.example files.
[root@simi ~]# cp /usr/share/doc/dhcp-server/dhcp.conf.exampe /etc/dhcp/dhcpd.conf
This is the main configuration file of the server. This file needs to be edited to create a DHCP server. You can use any text editor to edit the server’s main configuration file.
Edit Server configuration file
[root@simi ~]# vim /etc/dhcp/dhcpd.conf
after successfully configure configuration file then save and exit
Option domain-name: Enter the domain name of your server.
option domain-name-servers: Enter the DNS Server name OR IP of your server.
Lease time: the DHCP server will reserve the IP address for at least 600 seconds (default-lease-time) and at max 7200 seconds (max-lease-time) for Particulter Device, Other common values would be 86400 (one day), 604800 (one week), and 2592000 (30 days).
Start, Enable and check the DHCP Server Services
After successfully editing the DHCP server main configuration file, start its service and also check the status of the service.
systemctl start dhcpd systemctl enable dhcpd systemctl status dhcpd
Firewall setting
If the firewall services are running in your system then allow DHCP service uses port number 67
[root@simi ~]# firewall-cmd --add-service=dhcp permanent [root@simi ~]# firewall-cmd --reload
Configure DHCP Client
After successfully configuring the DHCP server, follow the below steps to get the IP address in the client machine
First Install DHCP-client packages if the package is not installed (generally installed by default).
[root@simi ~]#dnf install dhcp-client -y
To change the network connection type nmtui command in Terminal the Bellow screen displayed.
[root@simi ~]#nmtui
Clicking on the Edit a connection with the help of the keyboard Navigation Key and Press Enter.
Click ON enp0s3 and Hit Enter
NOTE enp0s3 is the name of your system’s network card, it may have a different name in your system
Select Automatic as shown in the screen below
With the help of keyboard click on ok option
Check IP Address Get from DHCP Server
In this way, the client PC will get the IP address from the DHCP server with the help of a command line.
addr show enp0s3 nmcli connection modify enp0s3 ipv4.mathod auto nmcli connection down enp0s3 nmcli connection enp0s3
Configure DHCP Client on Windows computer.
In this process, we will talk about how to receive IP Addresses from the DHCP server in the Windows client computer.
Open the network settings and select Internet Protocol Version 4 (RCP/IPv4) and Click On Properties Button
Check mark In Obtain IP Address Automatically and Click On OK.
Now Got The IP Address From DHCP Server.
