# Setup Pi-Hole as a Recursive DNS Server with Unbound

## Installing and Configuring Unbound

1. Run the following commands in a terminal window:
   # install unbound
   sudo apt install unbound
   # update root hints file
   wget https://www.internic.net/domain/named.root -qO- | sudo tee /var/lib/unbound/root.hints
   # edit unbound configuration
   sudo nano /etc/unbound/unbound.conf.d/pi-hole.conf
2. Paste the following configuration into 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.
   # Suggested by the unbound man page to reduce fragmentation reassembly problems
   edns-buffer-size: 1472

   # 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

3. Press CTRL+O, Enter, CTRL+X to write the changes to pi-hole.conf
4. Continue with the following commands in terminal
   # restart the unbound service
   sudo service unbound restart
   # test a DNS lookup via unbound
   dig github.io @127.0.0.1 -p 5335
5. Back in the web browser, navigate back to the Pi-Hole web interface
6. Log in if you are not already
7. Select Settings > DNS
8. Uncheck any of the previously selected upstream DNS servers
9. Check the box next to Custom 1 (IPv4)
10. Enter 127.0.0.1#5335 as the address
11. Scroll down and click the Save button

## Testing the Changes

1. Open a new tab in the web browser and navigate to https://yahoo.com
2. Go back into Pi-Hole and select Query Log from the left navigation
3. Filter the results on www.yahoo.com
4. You should see entries showing the DNS requests forwarding to localhost#5335