Dnsmasq

Related commands

• sudo systemd-resolve --flush-caches

Files of Interest

/var/lib/misc/dnsmasq.leases

Stub Resolver

• https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/plan/reviewing-dns-concepts#:~:text=in%20the%20namespace.-,Recursive%20name%20resolution,which%20it%20is%20not%20authoritative.&text=Forwarding%20and%20root%20hints%20are,which%20they%20are%20not%20authoritative.
• https://www.internetsociety.org/resources/deploy360/dns-privacy/intro/-
• https://www.omnisecu.com/tcpip/recursive-and-iterative-dns-queries.php#:~:text=Recursion%20in%20DNS%20(Domain%20Name,DNS%20Servers%20for%20name%20resolution.

Install

apt-get update && sudo apt-get install -y dnsmasq
systemctl stop systemd-resolved
touch /etc/dnsmasq.hosts
systemctl disable systemd-resolved
systemctl mask systemd-resolved

Undo

systemctl unmask systemd-resolved
systemctl enable systemd-resolved
systemctl start systemd-resolved

/etc/dnsmasq.hosts

10.0.0.1  prod.example.com.
10.0.0.2  dev.example.com.

/etc/dnsmasq.conf

no-resolv  # Don't read /etc/resolv.conf. Get upstream servers only from the command line or the dnsmasq  configuration file.
server=8.8.8.8
server=8.8.4.4
addn-hosts=/etc/dnsmasq.hosts
cache-size=1000  # Only cache up to 1000 names
listen-address=127.0.0.1,10.x.x.x  # must explicityly set this for non-local network resolves
# server=/example.com/ns.example.com  # forward example.com to server
# ...

systemctl restart dnsmasq
dig @10.x.x.x +short prod.example.com -p 15353
sudo tcpdump -npi eth0 port 53

Ref

• https://www.tecmint.com/setup-a-dns-dhcp-server-using-dnsmasq-on-centos-rhel/