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[Raspberry PI] Servidor DNS Recursivo +DNSSEC com Unbound

Neste tutorial será mostrado como configurar um Servidor de DNS local + DNSSEC usando o Raspberry Pi 3 + Unbound

O Raspberry Pi pode ser um bom aliado para solucionar problema em lentidão ao carregar páginas em uma rede pequena/média (0-1000 clientes), visto que o Unbound não consome muito recurso. Assim, pode ser muito bem utilizado em um Provedor de Internet
Suponho que você já está com o Rasperry pi OS instalado (sistema que usaremos neste tutorial, mas pode ser qualquer sistema linux/unix) , mas caso não, faça a instalação seguindo esse artigo do blog. Estando tudo Ok, vamos a instalação do serviço propriamente dita.

Antes de tudo, atualize o Raspberry Pi OS com os comandos:
apt update; apt upgrade -y

Pré-requisitos de software
Instale os pacotes abaixo:
apt install wget dnsutils dnstop build-essential libssl-dev net-tools mtr -y

Instalação do Unbound
A versão mais recente do Unbound ainda não está no repositório padrão do sistema, para instalar será necessário realizar a adição do repositório backports no Raspberry Pi OS e instalar somente o unbound.
echo "deb http://ftp.debian.org/debian buster-backports main" >> /etc/apt/sources.list
apt update
apt -t buster-backports install "unbound" -y

Em seguida, acessar a pasta que contém os arquivos do serviço Unbound e realizar o download do arquivo “named.cache” com a lista atualizada dos “root servers”.:
cd /etc/unbound
wget ftp://ftp.internic.net/domain/named.cache
Execute o comando “unbound-control-setup” para gerar os arquivos de chaves necessárias parao TLS e altere o proprietário da pasta “
/etc/unbound” e também as permissões.
unbound-control-setup
chown unbound:root unbound_* ; chmod 660 unbound_*
touch /var/log/unbound.log
Necessário edição das entradas do arquivo “unbound.conf” destacadas em vermelho abaixo, pelas informações relacionadas ao seu acesso. Para a edição do arquivo use o comando:
nano unbound.conf

server:
# verbosity number, 0 is least verbose. 1 is default.
verbosity: 0

# print statistics to the log (for every thread) every N seconds.
# Set to "" or 0 to disable. Default is disabled.
# statistics-interval: 0

# enable cumulative statistics, without clearing them after printing.
# statistics-cumulative: no

# enable extended statistics (query types, answer codes, status)
# printed from unbound-control. default off, because of speed.
# extended-statistics: no

# number of threads to create. 1 disables threading.
num-threads: 4

# specify the interfaces to answer queries from by ip-address.
# The default is to listen to localhost (127.0.0.1 and ::1).
# specify 0.0.0.0 and ::0 to bind to all available interfaces.
# specify every interface[@port] on a new 'interface:' labelled line.
# The listen interfaces are not changed on reload, only on restart.
interface: IP-DO-RASPBERRY-PI
interface: 127.0.0.1
# interface: 192.0.2.154@5003
#interface: 2804:3dcc:cafe::18

# enable this feature to copy the source address of queries to reply.
# Socket options are not supported on all platforms. experimental.
# interface-automatic: no

# port to answer queries from
port: 53

# specify the interfaces to send outgoing queries to authoritative
# server from by ip-address. If none, the default (all) interface
# is used. Specify every interface on a 'outgoing-interface:' line.
# outgoing-interface: 192.0.2.153
# outgoing-interface: 2001:DB8::5
# outgoing-interface: 2001:DB8::6

# Specify a netblock to use remainder 64 bits as random bits for
# upstream queries. Uses freebind option (Linux).
# outgoing-interface: 2001:DB8::/64
# Also (Linux:) ip -6 addr add 2001:db8::/64 dev lo
# And: ip -6 route add local 2001:db8::/64 dev lo
# And set prefer-ip6: yes to use the ip6 randomness from a netblock.
# Set this to yes to prefer ipv6 upstream servers over ipv4.
prefer-ip6: no

# number of ports to allocate per thread, determines the size of the
# port range that can be open simultaneously. About double the
# num-queries-per-thread, or, use as many as the OS will allow you.
outgoing-range: 462

# permit unbound to use this port number or port range for
# making outgoing queries, using an outgoing interface.
# outgoing-port-permit: 32768
# deny unbound the use this of port number or port range for
# making outgoing queries, using an outgoing interface.
# Use this to make sure unbound does not grab a UDP port that some
# other server on this computer needs. The default is to avoid
# IANA-assigned port numbers.
# If multiple outgoing-port-permit and outgoing-port-avoid options
# are present, they are processed in order.
# outgoing-port-avoid: "3200-3208"

# number of outgoing simultaneous tcp buffers to hold per thread.
# outgoing-num-tcp: 10

# number of incoming simultaneous tcp buffers to hold per thread.
# incoming-num-tcp: 10

# buffer size for UDP port 53 incoming (SO_RCVBUF socket option).
# 0 is system default. Use 4m to catch query spikes for busy servers.
so-rcvbuf: 4m

# buffer size for UDP port 53 outgoing (SO_SNDBUF socket option).
# 0 is system default. Use 4m to handle spikes on very busy servers.
so-sndbuf: 2m

# use SO_REUSEPORT to distribute queries over threads.
so-reuseport: yes

# use IP_TRANSPARENT so the interface: addresses can be non-local
# and you can config non-existing IPs that are going to work later on
# (uses IP_BINDANY on FreeBSD).
# ip-transparent: no

# use IP_FREEBIND so the interface: addresses can be non-local
# and you can bind to nonexisting IPs and interfaces that are down.
# Linux only. On Linux you also have ip-transparent that is similar.
# ip-freebind: no

# EDNS reassembly buffer to advertise to UDP peers (the actual buffer
# is set with msg-buffer-size). 1480 can solve fragmentation (timeouts).
# edns-buffer-size: 4096

# Maximum UDP response size (not applied to TCP response).
# Suggested values are 512 to 4096. Default is 4096. 65536 disables it.
# max-udp-size: 4096

# buffer size for handling DNS data. No messages larger than this
# size can be sent or received, by UDP or TCP. In bytes.
# msg-buffer-size: 65552

# the amount of memory to use for the message cache.
# plain value in bytes or you can append k, m or G. default is "4Mb".
msg-cache-size: 256m

# the number of slabs to use for the message cache.
# the number of slabs must be a power of 2.
# more slabs reduce lock contention, but fragment memory usage.
msg-cache-slabs: 4

# the number of queries that a thread gets to service.
num-queries-per-thread: 231

# if very busy, 50% queries run to completion, 50% get timeout in msec
# jostle-timeout: 200

# msec to wait before close of port on timeout UDP. 0 disables.
# delay-close: 0

# the amount of memory to use for the RRset cache.
# plain value in bytes or you can append k, m or G. default is "4Mb".
rrset-cache-size: 512m

# the number of slabs to use for the RRset cache.
# the number of slabs must be a power of 2.
# more slabs reduce lock contention, but fragment memory usage.
rrset-cache-slabs: 4

# the time to live (TTL) value lower bound, in seconds. Default 0.
# If more than an hour could easily give trouble due to stale data.
# cache-min-ttl: 0

# the time to live (TTL) value cap for RRsets and messages in the
# cache. Items are not cached for longer. In seconds.
cache-max-ttl: 86400

# the time to live (TTL) value cap for negative responses in the cache
# cache-max-negative-ttl: 3600

# the time to live (TTL) value for cached roundtrip times, lameness and
# EDNS version information for hosts. In seconds.
# infra-host-ttl: 900

# minimum wait time for responses, increase if uplink is long. In msec.
# infra-cache-min-rtt: 50

# the number of slabs to use for the Infrastructure cache.
# the number of slabs must be a power of 2.
# more slabs reduce lock contention, but fragment memory usage.
infra-cache-slabs: 4

# the maximum number of hosts that are cached (roundtrip, EDNS, lame).
infra-cache-numhosts: 100000

# define a number of tags here, use with local-zone, access-control.
# repeat the define-tag statement to add additional tags.
# define-tag: "tag1 tag2 tag3"

# Enable IPv4, "yes" or "no".
do-ip4: yes

# Enable IPv6, "yes" or "no".
do-ip6: no

# Enable UDP, "yes" or "no".
do-udp: yes

# Enable TCP, "yes" or "no".
do-tcp: yes

# upstream connections use TCP only (and no UDP), "yes" or "no"
# useful for tunneling scenarios, default no.
# tcp-upstream: no

# Maximum segment size (MSS) of TCP socket on which the server
# responds to queries. Default is 0, system default MSS.
# tcp-mss: 0

# Maximum segment size (MSS) of TCP socket for outgoing queries.
# Default is 0, system default MSS.
# outgoing-tcp-mss: 0

# Detach from the terminal, run in background, "yes" or "no".
do-daemonize: no

# control which clients are allowed to make (recursive) queries
# to this server. Specify classless netblocks with /size and action.
# By default everything is refused, except for localhost.
# Choose deny (drop message), refuse (polite error reply),
# allow (recursive ok), allow_snoop (recursive and nonrecursive ok)
# deny_non_local (drop queries unless can be answered from local-data)
# refuse_non_local (like deny_non_local but polite error reply).
# access-control: 0.0.0.0/0 refuse
# access-control: 127.0.0.0/8 allow
# access-control: ::0/0 refuse
# access-control: 127.0.0.0/8 allow
# access-control: ::0/0 refuse
# access-control: ::1 allow
# access-control: ::ffff:127.0.0.1 allow

access-control: IP-DA-OPERADORA allow  
access-control: 192.168.0.0/16 allow
access-control: 172.16.0.0/12 allow
access-control: 100.64.0.0/10 allow
access-control: 10.0.0.0/8 allow

# tag access-control with list of tags (in "" with spaces between)
# Clients using this access control element use localzones that
# are tagged with one of these tags.
# access-control-tag: 192.0.2.0/24 "tag2 tag3"

# set action for particular tag for given access control element
# if you have multiple tag values, the tag used to lookup the action
# is the first tag match between access-control-tag and local-zone-tag
# where "first" comes from the order of the define-tag values.
# access-control-tag-action: 192.0.2.0/24 tag3 refuse

# set redirect data for particular tag for access control element
# access-control-tag-data: 192.0.2.0/24 tag2 "A 127.0.0.1"

# Set view for access control element
# access-control-view: 192.0.2.0/24 viewname

# if given, a chroot(2) is done to the given directory.
# i.e. you can chroot to the working directory, for example,
# for extra security, but make sure all files are in that directory.
# 
# If chroot is enabled, you should pass the configfile (from the
# commandline) as a full path from the original root. After the
# chroot has been performed the now defunct portion of the config
# file path is removed to be able to reread the config after a reload.
#
# All other file paths (working dir, logfile, roothints, and
# key files) can be specified in several ways:
# o as an absolute path relative to the new root.
# o as a relative path to the working directory.
# o as an absolute path relative to the original root.
# In the last case the path is adjusted to remove the unused portion.
#
# The pid file can be absolute and outside of the chroot, it is
# written just prior to performing the chroot and dropping permissions.
#
# Additionally, unbound may need to access /dev/random (for entropy).
# How to do this is specific to your OS.
# 
# If you give "" no chroot is performed. The path must not end in a /.
# chroot: "/etc/unbound"

# if given, user privileges are dropped (after binding port),
# and the given username is assumed. Default is user "unbound".
# If you give "" no privileges are dropped.
username: "unbound"

# the working directory. The relative files in this config are
# relative to this directory. If you give "" the working directory
# is not changed.
# If you give a server: directory: dir before include: file statements
# then those includes can be relative to the working directory.
directory: "/etc/unbound"

# the log file, "" means log to stderr.
# Use of this option sets use-syslog to "no".
# logfile: "/etc/unbound/var/log/unbound.log"

# Log to syslog(3) if yes. The log facility LOG_DAEMON is used to
# log to. If yes, it overrides the logfile.
use-syslog: no
# Log identity to report. if empty, defaults to the name of argv[0]
# (usually "unbound").
# log-identity: ""

# print UTC timestamp in ascii to logfile, default is epoch in seconds.
# log-time-ascii: no

# print one line with time, IP, name, type, class for every query.
# log-queries: no

# the pid file. Can be an absolute path outside of chroot/work dir.
# pidfile: "/etc/unbound/unbound.pid"

# file to read root hints from.
# get one from https://www.internic.net/domain/named.cache
root-hints: "named.cache"

# enable to not answer id.server and hostname.bind queries.
hide-identity: yes

# enable to not answer version.server and version.bind queries.
hide-version: yes

# the identity to report. Leave "" or default to return hostname.
identity: "DNS"

# the version to report. Leave "" or default to return package version.
version: "DNS"

# the target fetch policy.
# series of integers describing the policy per dependency depth.
# The number of values in the list determines the maximum dependency
# depth the recursor will pursue before giving up. Each integer means:
# -1 : fetch all targets opportunistically,
# 0: fetch on demand,
# positive value: fetch that many targets opportunistically.
# Enclose the list of numbers between quotes ("").
# target-fetch-policy: "3 2 1 0 0"

# Harden against very small EDNS buffer sizes.
harden-short-bufsize: yes

# Harden against unseemly large queries.
harden-large-queries: yes

# Harden against out of zone rrsets, to avoid spoofing attempts.
harden-glue: yes

# Harden against receiving dnssec-stripped data. If you turn it
# off, failing to validate dnskey data for a trustanchor will
# trigger insecure mode for that zone (like without a trustanchor).
# Default on, which insists on dnssec data for trust-anchored zones.
harden-dnssec-stripped: yes

# Harden against queries that fall under dnssec-signed nxdomain names.
# harden-below-nxdomain: no

# Harden the referral path by performing additional queries for
# infrastructure data. Validates the replies (if possible).
# Default off, because the lookups burden the server. Experimental
# implementation of draft-wijngaards-dnsext-resolver-side-mitigation.
# harden-referral-path: no

# Harden against algorithm downgrade when multiple algorithms are
# advertised in the DS record. If no, allows the weakest algorithm
# to validate the zone.
# harden-algo-downgrade: no

# Sent minimum amount of information to upstream servers to enhance
# privacy. Only sent minimum required labels of the QNAME and set QTYPE
# to NS when possible.
# qname-minimisation: yes

# QNAME minimisation in strict mode. Do not fall-back to sending full
# QNAME to potentially broken nameservers. A lot of domains will not be
# resolvable when this option in enabled.
# This option only has effect when qname-minimisation is enabled.
qname-minimisation-strict: no

# Use 0x20-encoded random bits in the query to foil spoof attempts.
# This feature is an experimental implementation of draft dns-0x20.
use-caps-for-id: yes

# Domains (and domains in them) without support for dns-0x20 and
# the fallback fails because they keep sending different answers.
# caps-whitelist: "licdn.com"
# caps-whitelist: "senderbase.org"

# Enforce privacy of these addresses. Strips them away from answers.
# It may cause DNSSEC validation to additionally mark it as bogus.
# Protects against 'DNS Rebinding' (uses browser as network proxy).
# Only 'private-domain' and 'local-data' names are allowed to have
# these private addresses. No default.
# 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

# Allow the domain (and its subdomains) to contain private addresses.
# local-data statements are allowed to contain private addresses too.
# private-domain: "example.com"

# If nonzero, unwanted replies are not only reported in statistics,
# but also a running total is kept per thread. If it reaches the
# threshold, a warning is printed and a defensive action is taken,
# the cache is cleared to flush potential poison out of it.
# A suggested value is 10000000, the default is 0 (turned off).
# unwanted-reply-threshold: 0

# Do not query the following addresses. No DNS queries are sent there.
# List one address per entry. List classless netblocks with /size,
# do-not-query-address: 127.0.0.1/8
# do-not-query-address: ::1

# if yes, the above default do-not-query-address entries are present.
# if no, localhost can be queried (for testing and debugging).
do-not-query-localhost: no

# if yes, perform prefetching of almost expired message cache entries.
prefetch: yes

# if yes, perform key lookups adjacent to normal lookups.
prefetch-key: yes

# if yes, Unbound rotates RRSet order in response.
rrset-roundrobin: yes

# if yes, Unbound doesn't insert authority/additional sections
# into response messages when those sections are not required.
minimal-responses: yes

# true to disable DNSSEC lameness check in iterator.
# disable-dnssec-lame-check: no

# module configuration of the server. A string with identifiers
# separated by spaces. Syntax: "[dns64] [validator] iterator"
# module-config: "validator iterator"
# File with trusted keys, kept uptodate using RFC5011 probes,
# initial file like trust-anchor-file, then it stores metadata.
# Use several entries, one per domain name, to track multiple zones.
# 
# If you want to perform DNSSEC validation, run unbound-anchor before
# you start unbound (i.e. in the system boot scripts). And enable:
# Please note usage of unbound-anchor root anchor is at your own risk
# and under the terms of our LICENSE (see that file in the source).
# auto-trust-anchor-file: "/etc/unbound/root.key"

# File with DLV trusted keys. Same format as trust-anchor-file.
# There can be only one DLV configured, it is trusted from root down.
# DLV is going to be decommissioned. Please do not use it any more.
# dlv-anchor-file: "dlv.isc.org.key"

# File with trusted keys for validation. Specify more than one file
# with several entries, one file per entry.
# Zone file format, with DS and DNSKEY entries.
# Note this gets out of date, use auto-trust-anchor-file please.
# trust-anchor-file: ""

# Trusted key for validation. DS or DNSKEY. specify the RR on a
# single line, surrounded by "". TTL is ignored. class is IN default.
# Note this gets out of date, use auto-trust-anchor-file please.
# (These examples are from August 2007 and may not be valid anymore).
# trust-anchor: "nlnetlabs.nl. DNSKEY 257 3 5 AQPzzTWMz8qSWIQlfRnPckx2BiVmkVN6LPupO3mbz7FhLSnm26n6iG9N Lby97Ji453aWZY3M5/xJBSOS2vWtco2t8C0+xeO1bc/d6ZTy32DHchpW 6rDH1vp86Ll+ha0tmwyy9QP7y2bVw5zSbFCrefk8qCUBgfHm9bHzMG1U BYtEIQ=="
# trust-anchor: "jelte.nlnetlabs.nl. DS 42860 5 1 14D739EB566D2B1A5E216A0BA4D17FA9B038BE4A"

# File with trusted keys for validation. Specify more than one file
# with several entries, one file per entry. Like trust-anchor-file
# but has a different file format. Format is BIND-9 style format,
# the trusted-keys { name flag proto algo "key"; }; clauses are read.
# you need external update procedures to track changes in keys.
# trusted-keys-file: ""

# Ignore chain of trust. Domain is treated as insecure.
# domain-insecure: "example.com"

# Override the date for validation with a specific fixed date.
# Do not set this unless you are debugging signature inception
# and expiration. "" or "0" turns the feature off. -1 ignores date.
# val-override-date: ""

# The time to live for bogus data, rrsets and messages. This avoids
# some of the revalidation, until the time interval expires. in secs.
# val-bogus-ttl: 60

# The signature inception and expiration dates are allowed to be off
# by 10% of the signature lifetime (expir-incep) from our local clock.
# This leeway is capped with a minimum and a maximum. In seconds.
# val-sig-skew-min: 3600
# val-sig-skew-max: 86400

# Should additional section of secure message also be kept clean of
# unsecure data. Useful to shield the users of this validator from
# potential bogus data in the additional section. All unsigned data
# in the additional section is removed from secure messages.
# val-clean-additional: yes

# Turn permissive mode on to permit bogus messages. Thus, messages
# for which security checks failed will be returned to clients,
# instead of SERVFAIL. It still performs the security checks, which
# result in interesting log files and possibly the AD bit in
# replies if the message is found secure. The default is off.
# val-permissive-mode: no

# Ignore the CD flag in incoming queries and refuse them bogus data.
# Enable it if the only clients of unbound are legacy servers (w2008)
# that set CD but cannot validate themselves.
# ignore-cd-flag: no
# ignore-cd-flag: no

# Serve expired reponses from cache, with TTL 0 in the response,
# and then attempt to fetch the data afresh.
serve-expired: yes

# Have the validator log failed validations for your diagnosis.
# 0: off. 1: A line per failed user query. 2: With reason and bad IP.
# val-log-level: 0

# It is possible to configure NSEC3 maximum iteration counts per
# keysize. Keep this table very short, as linear search is done.
# A message with an NSEC3 with larger count is marked insecure.
# List in ascending order the keysize and count values.
# val-nsec3-keysize-iterations: "1024 150 2048 500 4096 2500"

# instruct the auto-trust-anchor-file probing to add anchors after ttl.
# add-holddown: 2592000 # 30 days

# instruct the auto-trust-anchor-file probing to del anchors after ttl.
# del-holddown: 2592000 # 30 days

# auto-trust-anchor-file probing removes missing anchors after ttl.
# If the value 0 is given, missing anchors are not removed.
# keep-missing: 31622400 # 366 days

# debug option that allows very small holddown times for key rollover,
# otherwise the RFC mandates probe intervals must be at least 1 hour.
# permit-small-holddown: no

# the amount of memory to use for the key cache.
# plain value in bytes or you can append k, m or G. default is "4Mb".
key-cache-size: 128m

# the number of slabs to use for the key cache.
# the number of slabs must be a power of 2.
# more slabs reduce lock contention, but fragment memory usage.
key-cache-slabs: 4

# the amount of memory to use for the negative cache (used for DLV).
# plain value in bytes or you can append k, m or G. default is "1Mb".
# neg-cache-size: 1m

# By default, for a number of zones a small default 'nothing here'
# reply is built-in. Query traffic is thus blocked. If you
# wish to serve such zone you can unblock them by uncommenting one
# of the nodefault statements below.
# You may also have to use domain-insecure: zone to make DNSSEC work,
# unless you have your own trust anchors for this zone.
# local-zone: "localhost." nodefault
# local-zone: "127.in-addr.arpa." nodefault
# local-zone: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa." nodefault
# local-zone: "onion." nodefault
# local-zone: "10.in-addr.arpa." nodefault
# local-zone: "16.172.in-addr.arpa." nodefault
# local-zone: "17.172.in-addr.arpa." nodefault
# local-zone: "18.172.in-addr.arpa." nodefault
# local-zone: "19.172.in-addr.arpa." nodefault
# local-zone: "20.172.in-addr.arpa." nodefault
# local-zone: "21.172.in-addr.arpa." nodefault
# local-zone: "22.172.in-addr.arpa." nodefault
# local-zone: "23.172.in-addr.arpa." nodefault
# local-zone: "24.172.in-addr.arpa." nodefault
# local-zone: "25.172.in-addr.arpa." nodefault
# local-zone: "26.172.in-addr.arpa." nodefault
# local-zone: "27.172.in-addr.arpa." nodefault
# local-zone: "28.172.in-addr.arpa." nodefault
# local-zone: "29.172.in-addr.arpa." nodefault
# local-zone: "30.172.in-addr.arpa." nodefault
# local-zone: "31.172.in-addr.arpa." nodefault
# local-zone: "168.192.in-addr.arpa." nodefault
# local-zone: "0.in-addr.arpa." nodefault
# local-zone: "254.169.in-addr.arpa." nodefault
# local-zone: "2.0.192.in-addr.arpa." nodefault
# local-zone: "100.51.198.in-addr.arpa." nodefault
# local-zone: "113.0.203.in-addr.arpa." nodefault
# local-zone: "255.255.255.255.in-addr.arpa." nodefault
# local-zone: "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa." nodefault
# local-zone: "d.f.ip6.arpa." nodefault
# local-zone: "8.e.f.ip6.arpa." nodefault
# local-zone: "9.e.f.ip6.arpa." nodefault
# local-zone: "a.e.f.ip6.arpa." nodefault
# local-zone: "b.e.f.ip6.arpa." nodefault
# local-zone: "8.b.d.0.1.0.0.2.ip6.arpa." nodefault
# And for 64.100.in-addr.arpa. to 127.100.in-addr.arpa.
local-zone: "wpad.domain.name" refuse
local-zone: "domain.name" refuse
local-zone: "cdntop.com" refuse
# If unbound is running service for the local host then it is useful
# to perform lan-wide lookups to the upstream, and unblock the
# long list of local-zones above. If this unbound is a dns server
# for a network of computers, disabled is better and stops information
# leakage of local lan information.
# unblock-lan-zones: no

# The insecure-lan-zones option disables validation for
# these zones, as if they were all listed as domain-insecure.
# insecure-lan-zones: no

# a number of locally served zones can be configured.
# local-zone:  
# local-data: ""
# o deny serves local data (if any), else, drops queries.
# o refuse serves local data (if any), else, replies with error.
# o static serves local data, else, nxdomain or nodata answer.
# o transparent gives local data, but resolves normally for other names
# o redirect serves the zone data for any subdomain in the zone.
# o nodefault can be used to normally resolve AS112 zones.
# o typetransparent resolves normally for other types and other names
# o inform acts like transparent, but logs client IP address
# o inform_deny drops queries and logs client IP address
# o always_transparent, always_refuse, always_nxdomain, resolve in
# that way but ignore local data for that name.
#
# defaults are localhost address, reverse for 127.0.0.1 and ::1
# and nxdomain for AS112 zones. If you configure one of these zones
# the default content is omitted, or you can omit it with 'nodefault'.
# 
# If you configure local-data without specifying local-zone, by
# default a transparent local-zone is created for the data.
# 
# You can add locally served data with
# local-zone: "local." static
# local-data: "mycomputer.local. IN A 192.0.2.51"
# local-data: 'mytext.local TXT "content of text record"'
# 
# You can override certain queries with
# local-data: "adserver.example.com A 127.0.0.1"
# 
# You can redirect a domain to a fixed address with
# (this makes example.com, www.example.com, etc, all go to 192.0.2.3)
# local-zone: "example.com" redirect
# local-data: "example.com A 192.0.2.3"
# 
# Shorthand to make PTR records, "IPv4 name" or "IPv6 name".
# You can also add PTR records using local-data directly, but then
# you need to do the reverse notation yourself.
# local-data-ptr: "192.0.2.3 www.example.com"

# tag a localzone with a list of tag names (in "" with spaces between)
# local-zone-tag: "example.com" "tag2 tag3"

# add a netblock specific override to a localzone, with zone type
# local-zone-override: "example.com" 192.0.2.0/24 refuse

# service clients over SSL (on the TCP sockets), with plain DNS inside
# the SSL stream. Give the certificate to use and private key.
# default is "" (disabled). requires restart to take effect.
# ssl-service-key: "path/to/privatekeyfile.key"
# ssl-service-pem: "path/to/publiccertfile.pem"
# ssl-port: 853

# request upstream over SSL (with plain DNS inside the SSL stream).
# Default is no. Can be turned on and off with unbound-control.
# ssl-upstream: no

# DNS64 prefix. Must be specified when DNS64 is use.
# Enable dns64 in module-config. Used to synthesize IPv6 from IPv4.
# dns64-prefix: 64:ff9b::0/96

# ratelimit for uncached, new queries, this limits recursion effort.
# ratelimiting is experimental, and may help against randomqueryflood.
# if 0(default) it is disabled, otherwise state qps allowed per zone.
# ratelimit: 0

# ratelimits are tracked in a cache, size in bytes of cache (or k,m).
# ratelimit-size: 4m
# ratelimit cache slabs, reduces lock contention if equal to cpucount.
# ratelimit-slabs: 4

# 0 blocks when ratelimited, otherwise let 1/xth traffic through
# ratelimit-factor: 10

# override the ratelimit for a specific domain name.
# give this setting multiple times to have multiple overrides.
# ratelimit-for-domain: example.com 1000
# override the ratelimits for all domains below a domain name
# can give this multiple times, the name closest to the zone is used.
# ratelimit-below-domain: com 1000

# Python config section. To enable:
# o use --with-pythonmodule to configure before compiling.
# o list python in the module-config string (above) to enable.
# o and give a python-script to run.
python:
# Script file to load
# python-script: "/etc/unbound/ubmodule-tst.py"

# Remote control config section.
remote-control:
# Enable remote control with unbound-control(8) here.
# set up the keys and certificates with unbound-control-setup.
# control-enable: no

# Set to no and use an absolute path as control-interface to use
# a unix local named pipe for unbound-control.
# control-use-cert: yes

# what interfaces are listened to for remote control.
# give 0.0.0.0 and ::0 to listen to all interfaces.
control-interface: 127.0.0.1
# control-interface: ::1

# port number for remote control operations.
control-port: 8953

# unbound server key file.
server-key-file: "/etc/unbound/unbound_server.key"

# unbound server certificate file.
server-cert-file: "/etc/unbound/unbound_server.pem"

# unbound-control key file.
control-key-file: "/etc/unbound/unbound_control.key"

# unbound-control certificate file.
control-cert-file: "/etc/unbound/unbound_control.pem"

# Stub zones.
# Create entries like below, to make all queries for 'example.com' and
# 'example.org' go to the given list of nameservers. list zero or more
# nameservers by hostname or by ipaddress. If you set stub-prime to yes,
# the list is treated as priming hints (default is no).
# With stub-first yes, it attempts without the stub if it fails.
# Consider adding domain-insecure: name and local-zone: name nodefault
# to the server: section if the stub is a locally served zone.
#stub-zone:
# name: "."
# stub-addr: 127.0.0.1
# stub-prime: no
# stub-first: no
# stub-ssl-upstream: no
# stub-zone:
# name: "example.org"
# stub-host: ns.example.com.

# Forward zones
# Create entries like below, to make all queries for 'example.com' and
# 'example.org' go to the given list of servers. These servers have to handle
# recursion to other nameservers. List zero or more nameservers by hostname
# or by ipaddress. Use an entry with name "." to forward all queries.
# If you enable forward-first, it attempts without the forward if it fails.
#forward-zone:
# name: "."
# forward-addr: 1.1.1.1
# forward-addr: 192.0.2.73@5355 # forward to port 5355.
# forward-first: yes
# forward-ssl-upstream: no
# forward-zone:
# name: "example.org"
# forward-host: fwd.example.com

# Views
# Create named views. Name must be unique. Map views to requests using
# the access-control-view option. Views can contain zero or more local-zone
# and local-data options. Options from matching views will override global
# options. Global options will be used if no matching view is found.
# With view-first yes, it will try to answer using the global local-zone and
# local-data elements if there is no view specific match.
# view:
# name: "viewname"
# local-zone: "example.com" redirect
# local-data: "example.com A 192.0.2.3"
# view-first: no
# view:
# name: "anotherview"
# local-zone: "example.com" refuse

#auto-trust-anchor-file: "/var/lib/unbound/root.key"

Em “access-control” você vai definir quem pode e quem não pode requisitar o servidor DNS. Na configuração está definida por padrão que toda a rede privada, seguindo a RFC1918, será aceita e o IP da sua operadora, que pode ser verificado acessando o site MeuIP. Caso queira, poderá deixar apenas a sua rede, ex: 192.168.0.0/24

Em “num-threads” você define quantos “cores” o serviço de DNS pode usar, configure com cuidado de acordo com seu CPU
Obs.: O Raspberry Pi OS possui 4. Para saber quantos “cores” seu processador possui, use o seguinte comando:
cat /proc/cpuinfo | grep processor | wc -l

Em “num-queries-per-thread” você define quantas requisições DNS podem ser processadas por cada “core” de seu CPU.

Agora verifique se encontre algum erro em seu “unbound.conf”.
unbound-checkconf /etc/unbound/unbound.conf
O resultado deverá ser igual a imagem a baixo:

Gerei um erro proposital (digitei errado o IP do Raspberry) no arquivo para poderem visualizar como o erro geralmente aparece:

Caso apresente erro, verifique novamente o arquivo de configuração unbound.conf seguindo detalhadamente todas as etapas do tutorial até aqui.
Caso não seja apresentado erros, reinicie o serviço e em seguida verifique o status
systemctl restart unbound
unbound-control status

Altere o arquivo resolv.conf deixado somente com “nameserver 127.0.0.1”
nano /etc/resolv.conf
nameserver 127.0.0.1

Realizando teste no servidor

Para testar seu DNS, execute o comando “dig” e o endereço do site que deseja, por exemplo:
Execute “dig www.google.com“, veja o “query time”,

Em seguida, após já ter sido armazenado em cache, execute novamente esse comando e veja que o “query time” deverá estar em 0msec

Em “status” deverá mostrar a mensagem “NOERROR”. Caso mostre “ServerFail”, alguma coisa não foi configurada corretamente. Verifique novamente o tutorial com calma e passo a passo.
Em “SERVER” deverá aparecer o IP de localhost, 127.0.0.1, indicando que as consultas de nome já está sendo resolvidas pelo próprio Raspberry Pi

Configuração de DNSSEC (Domain Name System SECurity extensions)

Após as ações descritas acima, em 99,9% dos casos, a chave DNSSEC já vai estar instalada. Por padrão “root.key” é instalado em /var/lib/unbound. Para confirmar, execute o comando*:
ls /var/lib/unbound
Partindo do pressuposto que já esteja lá, vamos apenas colocá-la em execução.
Iremos substituir o conteúdo arquivo original pelas linhas abaixo:
echo ". IN DS 19036 8 2 49AAC11D7B6F6446702E54A1607371607A1A41855200FD2CE1CDDE32F24E8FB5" > /var/lib/unbound/root.key
echo ". IN DS 20326 8 2 E06D44B80B8F1D39A95C0B0D7C65D08458E880409BBC683457104237C7F8EC8D" >> /var/lib/unbound/root.key

Criaremos o arquivo de log e alteraremos as permissões do arquivo “root.key”

touch /etc/unbound/unbound.log chown unbound:root /var/lib/unbound/root.key chmod 660 /var/lib/unbound/root.key

 Teste o arquivo “unbound.conf” novamente após as alterações realizadas e caso não apresente erros, reinicie novamente o serviço:
unbound-checkconf /etc/unbound/unbound.conf
systemctl restart unbound

Para testar o DNSSEC, execute o comando:
dig com. SOA +dnssec

Feito isso, você já está com seu servidor DNS + DNSSEC devidamente configurado em seu Raspberry PI 3 e já pode adiciona-lo em sua rede. Para isso, você deverá configurar o DNS do seu roteador com o IP do Raspberry PI, exemplificado abaixo com um roteador TPLINK e umas routerboard Mikrotik.
Configuração de DNS em TP Link

Configuração de DNS em RouterBoard Mikrotik (RouterOS)

*Obs.: E se não encontrar o “root.key” na pasta descrita, verifique na pasta “/etc/unbound/” caso não esteja, execute o comando abaixo: 
unbound-anchor -a /var/lib/unbound/root.key

 

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