Setting Up the Server's Network Interfaces

By default, the dhcpd service processes requests on those network interfaces that connect them to subnets that are defined in the DHCP configuration file.

Suppose that a DHCP server has mutliple interfaces. Through its interface enp0s1, the server is connected to the same subnet as the clients that the server is configured to serve. In this case, enp0s1 must be set in the DHCP service to enable the server to monitor and process incoming requests on that interface.

Before proceeding to either of the following procedures, ensure that you meet the following requirements:

You have the proper administrative privileges to configure DHCP.
You have installed the dhcp-server package.
If not, install the package with the following command:
```
sudo dnf install dhcp-server
```

Configure the network interfaces as follows:

For IPv4 networks:
1. Copy the /usr/lib/systemd/system/dhcpd.service file to the /etc/systemd/system/ directory.
```
sudo cp /usr/lib/systemd/system/dhcpd.service /etc/systemd/system/
```
2. Edit the /etc/systemd/system/dhcpd.service by locating the line that defines the ExecStart parameter.
3. Append the interface names on which the dhcpd service should listen.
  
  See the sample entries in bold.
```
ExecStart=/usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -group dhcpd --no-pid $DHCPDARGS int1-name int2-name
```
4. Reload the systemd manager configuration.
```
sudo systemctl daemon-reload
```
5. Restart the dhcpd service configuration.
```
sudo systemctl restart dhcpd.service
```
  Alternatively, you can also type:
```
sudo systemctl restart dhcpd
```
For IPv6 networks:
1. Copy the /usr/lib/systemd/system/dhcpd6.service file to the /etc/systemd/system/ directory.
```
sudo cp /usr/lib/systemd/system/dhcpd6.service /etc/systemd/system/
```
2. Edit the /etc/systemd/system/dhcpd6.service file by locating the line that defines the ExecStart parameter.
3. Append the names of the interfaces on which the dhcpd6 service should listen.
  
  See the sample entries in bold.
```
ExecStart=/usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd6.conf -user dhcpd -group dhcpd --no-pid $DHCPDARGS int1-name int2-name
```
4. Reload the systemd manager configuration.
```
sudo systemctl daemon-reload
```
5. Restart the dhcpd service configuration.
```
sudo systemctl restart dhcpd6.service
```
  Alternatively, you can also type:
```
sudo systemctl restart dhcpd6
```