This tutorial discusses how to install and setup DHCP server on Fedora29/Fedora28/CentOS 7. Hosts in in a TCP/IP network utilizes the Dynamic Host Configuration Protocol (DHCP) to automatically learn their IPv4 settings. The DHCP server can allow both permanent and temporary lease of IP addresses to the hosts in a network. Most commonly, the hosts are assigned temporary IP addresses such that whenever they are no longer in a network, the IP addresses that were previously assigned to them will be reclaimed and made available for other hosts.
Installing DHCP Server
sudo dnf install dhcp < Fedora sudo yum install dhcp < Fedora/CentOS
Setup DHCP Server
/etc/dhcp/dhcpd.conf. The Sample configuration file is located under /usr/share/doc/dhcp-server/dhcpd.conf.example. Therefore, you can optionally check this sample configuration to guide you on how to set up your dhcp configuration file or you can copy the sample configuration file to /etc/dhcp/dhcpd.conf overwriting the existing one and make necessary changes that best suits your network.sudo \cp /usr/share/doc/dhcp-server/dhcpd.conf.example /etc/dhcp/dhcpd.conf
-
Parameterswhich state how to perform a task, whether to perform a task, or what network configuration options to send to the client. -
Declarationswhich describe the topology of the network, describe the clients, provide addresses for the clients, or apply a group of parameters to a group of declarations.
sudo vim /etc/dhcp/dhcpd.conf
# option definitions common to all supported networks... # option domain-name "example.org"; < Comment or edit accordingly option domain-name "example.com";
# option domain-name-servers ns1.example.org, ns2.example.org; option domain-name-servers ns1.example.com, ns2.example.com;
default-lease-time 600; max-lease-time 7200;
# If this DHCP server is the official DHCP server for the local # network, the authoritative directive should be uncommented. #authoritative; < uncomment this line authoritative;
Subnet Declaration
In order for the DHCP server to understand the network topology, you need to define DHCP subnet. For example, to configure the DHCP for the 192.168.10.0/24 LAN network, the declaration is defined as shown below;
Note that you can only serve DHCP requests for a subnet for which there is an interface configured in that subnet on the host machine.
subnet 192.168.43.0 netmask 255.255.255.0 {
range 192.168.43.100 192.168.43.200;
option domain-name-servers ns1.example.com, ns2.example.com;
option domain-name "example.com";
option routers 192.168.43.1;
option broadcast-address 192.168.43.255;
option time-offset -18000; # Eastern Standard Time
}
Host Static IP address Assignment
hardware ethernet parameter within a host declaration.host test {
option host-name "test.com";
hardware ethernet 08:00:27:15:b4:72;
fixed-address 192.168.43.155;
}
Shared Network Declaration.
shared-network declaration. Parameters within the shared-network, but outside the enclosed subnet declarations, are considered to be global parameters.shared-network test {
# global parameters for shared network
option domain-search "example.com";
option domain-name-servers ns1.example.com, ns2.example.com;
option routers 192.168.25.2;
subnet 192.168.30.0 netmask 255.255.255.0 {
#parameters for subnet 192.168.30.0/24
range 192.168.30.1 192.168.30.254;
}
subnet 192.168.70.0 netmask 255.255.255.0 {
#parameters for subnet 192.168.70.0/24
range 192.168.70.1 192.168.70.254;
}
}
Group Declaration
group declaration is used to apply global parameters to a group of declarations.group {
option routers 192.168.10.3;
option subnet-mask 255.255.255.0;
option domain-search "example.com";
option domain-name-servers 192.168.10.1;
option time-offset -18000; # Eastern Standard Time
host server01 {
option host-name "srv01.example.com";
hardware ethernet 08:00:27:25:d4:72;
fixed-address 192.168.10.27;
}
host server02 {
option host-name "svr02.example.com";
hardware ethernet 08:00:27:05:b3:52;
fixed-address 192.168.10.30;
}
}
sudo systemctl start dhcpd sudo systemctl enable dhcpd
sudofirewall-cmd --add-service=dhcp --permanent sudo firewall-cmd --reload
DHCP Client Configuration
Now that your DHCP server is ready to serve out dynamic IP addresses, you can set up the DHCP client to validate all this. In this case am going to test this using Ubuntu 18 for static IP assignment (192.168.43.155) and Fedora 29 server for dynamic IP assignment within the range 192.168.43.100 192.168.43.200 as defined above.
