server: # If no logfile is specified, syslog is used # logfile: "/var/log/unbound/unbound.log" verbosity: 0 interface: 127.0.0.1 port: 5665 do-ip4: yes do-udp: yes do-tcp: yes # May be set to yes if you have IPv6 connectivity do-ip6: yes # 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: "/etc/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: 100.64.0.0/10 private-address: fd7a:115c:a1e0::/48 private-address: fd00::/8 private-address: fe80::/10