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Forked from MatthewVance/unbound.conf
Created May 11, 2021 10:59
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Config for running Unbound as a caching DNS forwarder (performance settings optimized for Raspberry Pi 2).
server:
###########################################################################
# BASIC SETTINGS
###########################################################################
# Time to live maximum for RRsets and messages in the cache. If the maximum
# kicks in, responses to clients still get decrementing TTLs based on the
# original (larger) values. When the internal TTL expires, the cache item
# has expired. Can be set lower to force the resolver to query for data
# often, and not trust (very large) TTL values.
cache-max-ttl: 86400
# Time to live minimum for RRsets and messages in the cache. If the minimum
# kicks in, the data is cached for longer than the domain owner intended,
# and thus less queries are made to look up the data. Zero makes sure the
# data in the cache is as the domain owner intended, higher values,
# especially more than an hour or so, can lead to trouble as the data in
# the cache does not match up with the actual data any more.
cache-min-ttl: 300
# Set the working directory for the program.
directory: "/opt/unbound/etc/unbound"
# RFC 6891. Number of bytes size to advertise as the EDNS reassembly buffer
# size. This is the value put into datagrams over UDP towards peers.
# 4096 is RFC recommended. 1472 has a reasonable chance to fit within a
# single Ethernet frame, thus lessing the chance of fragmentation
# reassembly problems (usually seen as timeouts). Setting to 512 bypasses
# even the most stringent path MTU problems, but is not recommended since
# the amount of TCP fallback generated is excessive.
edns-buffer-size: 1472
# Listen to for queries from clients and answer from this network interface
# and port.
interface: 0.0.0.0@53
# Rotates RRSet order in response (the pseudo-random number is taken from
# the query ID, for speed and thread safety).
rrset-roundrobin: yes
# Drop user privileges after binding the port.
username: "_unbound"
###########################################################################
# LOGGING
###########################################################################
# Do not print log lines to inform about local zone actions
log-local-actions: no
# Do not print one line per query to the log
log-queries: no
# Do not print one line per reply to the log
log-replies: no
# Do not print log lines that say why queries return SERVFAIL to clients
log-servfail: no
# Further limit logging
logfile: /dev/null
# Only log errors
verbosity: 0
###########################################################################
# PRIVACY SETTINGS
###########################################################################
# RFC 8198. Use the DNSSEC NSEC chain to synthesize NXDO-MAIN and other
# denials, using information from previous NXDO-MAINs answers. In other
# words, use cached NSEC records to generate negative answers within a
# range and positive answers from wildcards. This increases performance,
# decreases latency and resource utilization on both authoritative and
# recursive servers, and increases privacy. Also, it may help increase
# resilience to certain DoS attacks in some circumstances.
aggressive-nsec: yes
# Extra delay for timeouted UDP ports before they are closed, in msec.
# This prevents very delayed answer packets from the upstream (recursive)
# servers from bouncing against closed ports and setting off all sort of
# close-port counters, with eg. 1500 msec. When timeouts happen you need
# extra sockets, it checks the ID and remote IP of packets, and unwanted
# packets are added to the unwanted packet counter.
delay-close: 10000
# Prevent the unbound server from forking into the background as a daemon
do-daemonize: no
# Add localhost to the do-not-query-address list.
do-not-query-localhost: no
# Number of bytes size of the aggressive negative cache.
neg-cache-size: 4M
# Send minimum amount of information to upstream servers to enhance
# privacy (best privacy).
qname-minimisation: yes
###########################################################################
# SECURITY SETTINGS
###########################################################################
# Only give access to recursion clients from LAN IPs
access-control: 127.0.0.1/32 allow
access-control: 192.168.0.0/16 allow
access-control: 172.16.0.0/12 allow
access-control: 10.0.0.0/8 allow
# access-control: fc00::/7 allow
# access-control: ::1/128 allow
# File with trust anchor for one zone, which is tracked with RFC5011
# probes.
auto-trust-anchor-file: "var/root.key"
# Enable chroot (i.e, change apparent root directory for the current
# running process and its children)
chroot: "/opt/unbound/etc/unbound"
# Deny queries of type ANY with an empty response.
deny-any: yes
# Harden against algorithm downgrade when multiple algorithms are
# advertised in the DS record.
harden-algo-downgrade: yes
# RFC 8020. returns nxdomain to queries for a name below another name that
# is already known to be nxdomain.
harden-below-nxdomain: yes
# Require DNSSEC data for trust-anchored zones, if such data is absent, the
# zone becomes bogus. If turned off you run the risk of a downgrade attack
# that disables security for a zone.
harden-dnssec-stripped: yes
# Only trust glue if it is within the servers authority.
harden-glue: yes
# Ignore very large queries.
harden-large-queries: yes
# Perform additional queries for infrastructure data to harden the referral
# path. Validates the replies if trust anchors are configured and the zones
# are signed. This enforces DNSSEC validation on nameserver NS sets and the
# nameserver addresses that are encountered on the referral path to the
# answer. Experimental option.
harden-referral-path: no
# Ignore very small EDNS buffer sizes from queries.
harden-short-bufsize: yes
# Refuse id.server and hostname.bind queries
hide-identity: yes
# Refuse version.server and version.bind queries
hide-version: yes
# Report this identity rather than the hostname of the server.
identity: "DNS"
# These private network addresses are not allowed to be returned for public
# internet names. Any occurrence of such addresses are removed from DNS
# answers. Additionally, the DNSSEC validator may mark the answers bogus.
# This protects against DNS Rebinding
private-address: 10.0.0.0/8
private-address: 172.16.0.0/12
private-address: 192.168.0.0/16
private-address: 169.254.0.0/16
# private-address: fd00::/8
# private-address: fe80::/10
# private-address: ::ffff:0:0/96
# Enable ratelimiting of queries (per second) sent to nameserver for
# performing recursion. More queries are turned away with an error
# (servfail). This stops recursive floods (e.g., random query names), but
# not spoofed reflection floods. Cached responses are not rate limited by
# this setting. Experimental option.
ratelimit: 1000
# Use this certificate bundle for authenticating connections made to
# outside peers (e.g., auth-zone urls, DNS over TLS connections).
tls-cert-bundle: /etc/ssl/certs/ca-certificates.crt
# Set the total number of unwanted replies to eep track of in every thread.
# When it reaches the threshold, a defensive action of clearing the rrset
# and message caches is taken, hopefully flushing away any poison.
# Unbound suggests a value of 10 million.
unwanted-reply-threshold: 10000
# Use 0x20-encoded random bits in the query to foil spoof attempts. This
# perturbs the lowercase and uppercase of query names sent to authority
# servers and checks if the reply still has the correct casing.
# This feature is an experimental implementation of draft dns-0x20.
# Experimental option.
use-caps-for-id: yes
# Help protect users that rely on this validator for authentication from
# potentially bad data in the additional section. Instruct the validator to
# remove data from the additional section of secure messages that are not
# signed properly. Messages that are insecure, bogus, indeterminate or
# unchecked are not affected.
val-clean-additional: yes
###########################################################################
# PERFORMANCE SETTINGS
###########################################################################
# https://nlnetlabs.nl/documentation/unbound/howto-optimise/
# Number of slabs in the infrastructure cache. Slabs reduce lock contention
# by threads. Must be set to a power of 2.
infra-cache-slabs: 4
# Number of slabs in the key cache. Slabs reduce lock contention by
# threads. Must be set to a power of 2. Setting (close) to the number
# of cpus is a reasonable guess.
key-cache-slabs: 4
# Number of bytes size of the message cache.
# Unbound recommendation is to Use roughly twice as much rrset cache memory
# as you use msg cache memory.
msg-cache-size: 128525653
# Number of slabs in the message cache. Slabs reduce lock contention by
# threads. Must be set to a power of 2. Setting (close) to the number of
# cpus is a reasonable guess.
msg-cache-slabs: 4
# The number of queries that every thread will service simultaneously. If
# more queries arrive that need servicing, and no queries can be jostled
# out (see jostle-timeout), then the queries are dropped.
# This is best set at half the number of the outgoing-range.
# This Unbound instance was compiled with libevent so it can efficiently
# use more than 1024 file descriptors.
num-queries-per-thread: 4096
# The number of threads to create to serve clients.
# This is set dynamically at run time to effectively use available CPUs
# resources
num-threads: 3
# Number of ports to open. This number of file descriptors can be opened
# per thread.
# This Unbound instance was compiled with libevent so it can efficiently
# use more than 1024 file descriptors.
outgoing-range: 8192
# Number of bytes size of the RRset cache.
# Use roughly twice as much rrset cache memory as msg cache memory
rrset-cache-size: 257051306
# Number of slabs in the RRset cache. Slabs reduce lock contention by
# threads. Must be set to a power of 2.
rrset-cache-slabs: 4
# Do no insert authority/additional sections into response messages when
# those sections are not required. This reduces response size
# significantly, and may avoid TCP fallback for some responses. This may
# cause a slight speedup.
minimal-responses: yes
# # Fetch the DNSKEYs earlier in the validation process, when a DS record
# is encountered. This lowers the latency of requests at the expense of
# little more CPU usage.
prefetch: yes
# Fetch the DNSKEYs earlier in the validation process, when a DS record is
# encountered. This lowers the latency of requests at the expense of little
# more CPU usage.
prefetch-key: yes
# Have unbound attempt to serve old responses from cache with a TTL of 0 in
# the response without waiting for the actual resolution to finish. The
# actual resolution answer ends up in the cache later on.
serve-expired: yes
# Open dedicated listening sockets for incoming queries for each thread and
# try to set the SO_REUSEPORT socket option on each socket. May distribute
# incoming queries to threads more evenly.
so-reuseport: yes
###########################################################################
# LOCAL ZONE
###########################################################################
# Include file for local-data and local-data-ptr
include: /opt/unbound/etc/unbound/a-records.conf
###########################################################################
# FORWARD ZONE
###########################################################################
forward-zone:
# Forward all queries (except those in cache and local zone) to
# upstream recursive servers
name: "."
# Queries to this forward zone use TLS
forward-tls-upstream: yes
# https://dnsprivacy.org/wiki/display/DP/DNS+Privacy+Test+Servers
# Cloudflare
forward-addr: 1.1.1.1@853#cloudflare-dns.com
forward-addr: 1.0.0.1@853#cloudflare-dns.com
#forward-addr: 2606:4700:4700::1111@853#cloudflare-dns.com
#forward-addr: 2606:4700:4700::1001@853#cloudflare-dns.com
# CleanBrowsing
forward-addr: 185.228.168.9@853#security-filter-dns.cleanbrowsing.org
forward-addr: 185.228.169.9@853#security-filter-dns.cleanbrowsing.org
# forward-addr: 2a0d:2a00:1::2@853#security-filter-dns.cleanbrowsing.org
# forward-addr: 2a0d:2a00:2::2@853#security-filter-dns.cleanbrowsing.org
# Quad9
# forward-addr: 9.9.9.9@853#dns.quad9.net
# forward-addr: 149.112.112.112@853#dns.quad9.net
# forward-addr: 2620:fe::fe@853#dns.quad9.net
# forward-addr: 2620:fe::9@853#dns.quad9.net
# getdnsapi.net
# forward-addr: 185.49.141.37@853#getdnsapi.net
# forward-addr: 2a04:b900:0:100::37@853#getdnsapi.net
# Surfnet
# forward-addr: 145.100.185.15@853#dnsovertls.sinodun.com
# forward-addr: 145.100.185.16@853#dnsovertls1.sinodun.com
# forward-addr: 2001:610:1:40ba:145:100:185:15@853#dnsovertls.sinodun.com
# forward-addr: 2001:610:1:40ba:145:100:185:16@853#dnsovertls1.sinodun.com
remote-control:
control-enable: no
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