Linux Ubuntu Server DHCP

Table of Contents

1. Source
2. Install
3. Configure
4. Start & Enable
5. Confirm
6. Disable Router’s DHCP

1. Source

2. Install

Update package index and Install

sudo apt update -y && sudo apt install isc-dhcp-server -y

3. Configure

Assign the network interface that DHCP should run on
1. Edit file
  sudo vi /etc/default/isc-dhcp-server
2. Update contents for the INTERFACESv4 item
  Example where the network interface is eno1
  INTERFACESv4="eno1"

Edit config file dhcp.conf

Edit file
```
sudo vi /etc/dhcp/dhcpd.conf
```

Update contents

Sample contents

# https://help.ubuntu.com/community/isc-dhcp-server
#
default-lease-time 600;
max-lease-time 7200;

subnet 192.168.1.0 netmask 255.255.255.0 {
    range 192.168.1.3 192.168.1.250;
    option routers 192.168.1.1;
    option domain-name-servers 192.168.1.2,8.8.8.8;
    option domain-name "xackleystudio.local";
}

host p-ubuntu-norco {
  hardware ethernet 0c:c4:7a:7d:4d:74; # Device eno3
  fixed-address 192.168.1.3; # The desired static IP address
}

host p-ubuntu-nas {
  hardware ethernet 00:25:22:f8:3e:af; # Replace with the device's MAC address
  fixed-address 192.168.1.10; # The desired static IP address
}

Check file for errors
```
/usr/sbin/dhcpd -t
```

4. Start & Enable

Start
```
sudo systemctl start isc-dhcp-server
```
Enable
```
sudo systemctl enable isc-dhcp-server
```
Verify
```
sudo systemctl status isc-dhcp-server
```

5. Confirm

Look for leases
```
cat /var/lib/dhcp/dhcpd.leases
```

6. Disable Router’s DHCP

Confirm that the DHCP server is functioning before disabling the DHCP in the Router!

The router is currently serving as a DHCP server but this will be disabled to allow the isc-dhcp-server server to take over this role.
1. Disable the DHCP setting in the router: