Step 1: Installing Dnsmasq on Ubuntu 18.04

Run the following commands to disable the resolved service:

$ sudo systemctl disable systemd-resolved

$ sudo systemctl stop systemd-resolved

Also, remove the symlinked resolv.conf file $ ls -lh /etc/resolv.conf

lrwxrwxrwx 1 root root 39 Aug  8 15:52 /etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf

$ sudo rm /etc/resolv.conf

Then create new resolv.conf file.

$ sudo nano /etc/resolv.conf

nameserver 8.8.8.8

$ sudo apt-get install dnsmasq

$ sudo nano /etc/dnsmasq.conf

If you want to enable DNSSEC validation and caching, uncomment

#dnssec

Make any other changes you see relevant and restart dnsmasq when done:

$ sudo systemctl restart dnsmasq

Step 2: Adding DNS records to Dnsmasq

$ sudo vim /etc/hosts

10.1.3.4 server1.mypridomain.com
10.1.4.4 erp.mypridomain.com 
192.168.10.2 checkout.mypridomain.com 
192.168.4.3 hello.world

$ sudo systemctl restart dnsmasq

Step 3: Testing Dnsmasq DNS functionality

$ sudo vim /etc/resolv.conf

nameserver 127.0.0.1
nameserver 8.8.8.8

#Configure Dnsmasq as DHCP Server

• Default gateway IP address
• DNS server IP address (Probably Dnsmasq or different DNS server)
• Network Subnet mask
• DHCP Addresses range
• NTP server

See below example

dhcp-range=192.168.40.130,192.168.40.230,24h
dhcp-option=option:router,192.168.40.254
dhcp-option=option:dns-server,192.168.40.254
dhcp-option=option:netmask,255.255.255.0

Restart dnsmasq and configure clients to obtain an IP address from this server.

$ sudo systemctl restart dnsmasq