Install Unbound

sudo apt install unbound

wget https://www.internic.net/domain/named.root -qO- | sudo tee /var/lib/unbound/root.hints
sudo nano /etc/unbound/unbound.conf.d/pi-hole.conf

server:
# If no logfile is specified, syslog is used
# logfile: „/var/log/unbound/unbound.log“
verbosity: 0

interface: 127.0.0.1
port: 5335
do-ip4: yes
do-udp: yes
do-tcp: yes

# May be set to yes if you have IPv6 connectivity
do-ip6: no

# You want to leave this to no unless you have *native* IPv6. With 6to4 and
# Terredo tunnels your web browser should favor IPv4 for the same reasons
prefer-ip6: no

# Use this only when you downloaded the list of primary root servers!
# If you use the default dns-root-data package, unbound will find it automatically
#root-hints: „/var/lib/unbound/root.hints“

# Trust glue only if it is within the server’s authority
harden-glue: yes

# Require DNSSEC data for trust-anchored zones, if such data is absent, the zone becomes BOGUS
harden-dnssec-stripped: yes

# Don’t use Capitalization randomization as it known to cause DNSSEC issues sometimes
# see https://discourse.pi-hole.net/t/unbound-stubby-or-dnscrypt-proxy/9378 for further details
use-caps-for-id: no

# Reduce EDNS reassembly buffer size.
# IP fragmentation is unreliable on the Internet today, and can cause
# transmission failures when large DNS messages are sent via UDP. Even
# when fragmentation does work, it may not be secure; it is theoretically
# possible to spoof parts of a fragmented DNS message, without easy
# detection at the receiving end. Recently, there was an excellent study
# >>> Defragmenting DNS – Determining the optimal maximum UDP response size for DNS <<< # by Axel Koolhaas, and Tjeerd Slokker (https://indico.dns-oarc.net/event/36/contributions/776/) # in collaboration with NLnet Labs explored DNS using real world data from the # the RIPE Atlas probes and the researchers suggested different values for # IPv4 and IPv6 and in different scenarios. They advise that servers should # be configured to limit DNS messages sent over UDP to a size that will not # trigger fragmentation on typical network links. DNS servers can switch # from UDP to TCP when a DNS response is too big to fit in this limited # buffer size. This value has also been suggested in DNS Flag Day 2020. edns-buffer-size: 1232 # Perform prefetching of close to expired message cache entries # This only applies to domains that have been frequently queried prefetch: yes # One thread should be sufficient, can be increased on beefy machines. In reality for most users running on small networks or on a single machine, it should be unnecessary to seek performance enhancement by increasing num-threads above 1. num-threads: 1 # Ensure kernel buffer is large enough to not lose messages in traffic spikes so-rcvbuf: 1m # Ensure privacy of local IP ranges private-address: 192.168.0.0/16 private-address: 169.254.0.0/16 private-address: 172.16.0.0/12 private-address: 10.0.0.0/8 private-address: fd00::/8 private-address: fe80::/10 sudo nano /etc/unbound/unbound.conf.d/pi-hole.conf # Enable DNS over TLS with Unbound and Cloudflare tls-cert-bundle: /etc/ssl/certs/ca-certificates.crt forward-zone: name: "." forward-tls-upstream: yes # Cloudflare DNS forward-addr: 2606:4700:4700::1111@853#cloudflare-dns.com forward-addr: 1.1.1.1@853#cloudflare-dns.com forward-addr: 2606:4700:4700::1001@853#cloudflare-dns.com forward-addr: 1.0.0.1@853#cloudflare-dns.com sudo service unbound restart sudo service unbound status 127.0.0.1#5335