CentOS 7에서 Unbound를 설치하고 DNSSEC을 활성화하여 사용하는 방법

CentOS 7에서 Unbound를 설치하고 DNSSEC을 활성화하여 사용하는 방법

Unbound는 고성능의 캐싱 리졸버로 DNSSEC 검증 기능을 지원하여 클라이언트가 요청한 DNS 응답에 대해 DNSSEC 서명을 검증할 수 있습니다. DNSSEC을 통해 Unbound는 서명된 DNS 레코드를 확인하고 그 결과를 클라이언트에게 제공합니다.

1. Unbound 설치

Unbound를 설치합니다.

sudo yum install unbound

unbound -v

$ unbound -v
[1728125345] unbound[2848:0] notice: Start of unbound 1.6.6.

2. Unbound 설정 파일 구성

설정 파일 백업

cp /etc/unbound/unbound.conf /etc/unbound/unbound.conf.backup

Unbound의 설정 파일은 /etc/unbound/unbound.conf에 있습니다.

• auto-trust-anchor-file : 루트 키 파일 경로를 설정합니다. Unbound는 이 파일을 사용해 DNSSEC 신뢰 체인을 검증합니다.
• harden-dnssec-stripped : DNSSEC 서명이 제거된 응답을 강화해 무결성을 검증합니다.
• harden-algo-downgrade : 오래된 암호화 알고리즘에 대한 하향 강화를 설정합니다.

vim /etc/unbound/unbound.conf

server:
    # 기본 포트 설정
    port: 53

    # DNSSEC 검증 활성화
    do-ip4: yes
    do-udp: yes
    do-tcp: yes
    do-daemonize: yes

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

    # DNSSEC 관련 플래그
    harden-dnssec-stripped: yes
    harden-referral-path: yes
    harden-algo-downgrade: yes

    # 캐시 설정
    cache-max-ttl: 86400
    cache-min-ttl: 3600

    # 로그 수준 (디버깅 용)
    verbosity: 1

---

cat /etc/unbound/unbound.conf

#
# See unbound.conf(5) man page.
#
# this is a comment.

#Use this to include other text into the file.
#include: "otherfile.conf"

# The server clause sets the main parameters.
server:
	# whitespace is not necessary, but looks cleaner.

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

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

	# enable shm for stats, default no.  if you enable also enable
	# statistics-interval, every time it also writes stats to the
	# shared memory segment keyed with shm-key.
	# shm-enable: no

	# shm for stats uses this key, and key+1 for the shared mem segment.
	# shm-key: 11777

	# enable cumulative statistics, without clearing them after printing.
	# Needs to be disabled for munin plugin
	statistics-cumulative: no

	# enable extended statistics (query types, answer codes, status)
	# printed from unbound-control. default off, because of speed.
	# Needs to be enabled for munin plugin
	extended-statistics: yes

	# 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: 0.0.0.0
	# interface: ::0
	# interface: 192.0.2.153
	# interface: 192.0.2.154
	# interface: 192.0.2.154@5003
	# interface: 2001:DB8::5
	#
	# for dns over tls and raw dns over port 80
	# interface: 0.0.0.0@443
	# interface: ::0@443
	# interface: 0.0.0.0@80
	# interface: ::0@80

	# enable this feature to copy the source address of queries to reply.
	# Socket options are not supported on all platforms. experimental.
	# interface-automatic: yes
	#
	# NOTE: Enable this option when specifying interface 0.0.0.0 or ::0
	# NOTE: Disabled per Fedora policy not to listen to * on default install
	# NOTE: If deploying on non-default port, eg 80/443, this needs to be disabled
	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: 4096

	# permit unbound to use this port number or port range for
	# making outgoing queries, using an outgoing interface.
	# outgoing-port-permit: 32768-65535

	# 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: 0-32767

	# 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: 0

	# 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: 0

	# 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: yes

	# 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). 1472 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.
	# 3072 causes +dnssec any isc.org queries to need TC=1.
	# Helps mitigating DDOS
	# max-udp-size: 3072

	# 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: 4m

	# 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: 1024

	# 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: 4m

	# 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: 10000

	# 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: yes

	# Enable UDP, "yes" or "no".
	# NOTE: if setting up an unbound on tls443 for public use, you might want to
	# disable UDP to avoid being used in DNS amplification attacks.
	# 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".
	# Set the value to "no" when unbound runs as systemd service.
	# do-daemonize: yes

	# 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: ::1 allow
	# access-control: ::ffff:127.0.0.1 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: "/var/lib/unbound"
	chroot: ""

	# 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: ""

	# Log to syslog(3) if yes. The log facility LOG_DAEMON is used to
	# log to, with identity "unbound". If yes, it overrides the logfile.
	# use-syslog: yes

	# 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: yes

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

	# print one line per reply, with time, IP, name, type, class, rcode,
	# timetoresolve, fromcache and responsesize.
	# log-replies: no

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

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

	# enable to not answer id.server and hostname.bind queries.
	# hide-identity: no

	# enable to not answer version.server and version.bind queries.
	# hide-version: no

	# enable to not answer trustanchor.unbound queries.
	# hide-trustanchor: no

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

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

	# 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: no

	# Harden against unseemly large queries.
	# harden-large-queries: no

	# 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: yes

	# 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: yes

	# 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: no

	# 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: no

	# 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: 10000000

	# 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: yes

	# 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"
	module-config: "ipsecmod 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: "/var/lib/unbound/root.key"

	# trust anchor signaling sends a RFC8145 key tag query after priming.
	trust-anchor-signaling: yes

	# 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: ""
	#
	trusted-keys-file: /etc/unbound/keys.d/*.key
	auto-trust-anchor-file: "/var/lib/unbound/root.key"

	# 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.
	# NOTE: TURNING THIS ON DISABLES ALL DNSSEC SECURITY
	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

	# Serve expired responses from cache, with TTL 0 in the response,
	# and then attempt to fetch the data afresh.
	# serve-expired: no

	# 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: 1

	# 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: 4m

	# 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: "test." nodefault
	# local-zone: "invalid." 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.

	# 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

	# 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: <zone> <type>
	# 	local-data: "<resource record string>"
	# 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 resolves normally, 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"

	include: /etc/unbound/local.d/*.conf

	# 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: "/etc/unbound/unbound_server.key"
	# ssl-service-pem: "/etc/unbound/unbound_server.pem"
	# ssl-port: 443
	#
	# 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

	# global query ratelimit for all ip addresses.
	# feature is experimental.
	# if 0(default) it is disabled, otherwise states qps allowed per ip address
	# ip-ratelimit: 0

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

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

	# Specific options for ipsecmod.
	#
	# Enable or disable ipsecmod (it still needs to be defined in
	# module-config above). Can be used when ipsecmod needs to be
	# enabled/disabled via remote-control(below).
	ipsecmod-enabled: no
	#
	# Path to executable external hook. It must be defined when ipsecmod is
	# listed in module-config (above).
	ipsecmod-hook: "/usr/libexec/ipsec/_unbound-hook"
	#
	# When enabled unbound will reply with SERVFAIL if the return value of
	# the ipsecmod-hook is not 0.
	# ipsecmod-strict: no
	#
	# Maximum time to live (TTL) for cached A/AAAA records with IPSECKEY.
	# ipsecmod-max-ttl: 3600
	#
	# Reply with A/AAAA even if the relevant IPSECKEY is bogus. Mainly used for
	# testing.
	# ipsecmod-ignore-bogus: no
	#
	# Domains for which ipsecmod will be triggered. If not defined (default)
	# all domains are treated as being whitelisted.
	# ipsecmod-whitelist: "example.com"
	# ipsecmod-whitelist: "nlnetlabs.nl"

# 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.
	# Note: required for unbound-munin package
	control-enable: yes

	# 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 and Forward zones
include: /etc/unbound/conf.d/*.conf

# 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: "example.com"
#	stub-addr: 192.0.2.68
#	stub-prime: no
#	stub-first: no
#	stub-ssl-upstream: no
# stub-zone:
#	name: "example.org"
#	stub-host: ns.example.com.

# You can now also dynamically create and delete stub-zone's using
# unbound-control stub_add domain.com 1.2.3.4 5.6.7.8
# unbound-control stub_remove domain.com 1.2.3.4 5.6.7.8

# 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: "example.com"
# 	forward-addr: 192.0.2.68
# 	forward-addr: 192.0.2.73@5355  # forward to port 5355.
# 	forward-first: no
# 	forward-ssl-upstream: no
# forward-zone:
# 	name: "example.org"
# 	forward-host: fwd.example.com
#
# You can now also dynamically create and delete forward-zone's using
# unbound-control forward_add domain.com 1.2.3.4 5.6.7.8
# unbound-control forward_remove domain.com 1.2.3.4 5.6.7.8

# 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"
# 	local-data-ptr: "192.0.2.3 www.example.com"
#	view-first: no
# view:
#	name: "anotherview"
#	local-zone: "example.com" refuse

cat /etc/unbound/conf.d/example.com.conf

# Example of an override of the "public DNS tree" with an "internal view"
# override, for example to add an internal-only corporate DNS zone.
#
# The stub-zone/stub-addr must point to AUTHORITATIVE servers. If you want to
# point to an internal RECURSIVE server, use forward-zone/forward-addr instead.

#stub-zone:
#	name: example.com
#	stub-prime: no
#	# if you could trust a lookup, use:
#	stub-host: a.iana-servers.net.
#	stub-host: b.iana-servers.net.
#	# else specify the IP's using:
#	stub-addr: 199.43.132.53
#	stub-addr: 2001:500:8c::53
#	stub-addr: 199.43.133.53
#	stub-addr: 2001:500:8d::53

---

Unbound 설정 확인

sudo unbound-checkconf

3. 루트 신뢰 앵커 (Root Trust Anchor) 업데이트

Unbound는 DNSSEC 검증을 위해 루트 신뢰 앵커 파일이 필요합니다. 이 파일은 DNSSEC의 루트 키를 포함하고 있습니다.

 

루트 신뢰 앵커를 업데이트합니다.

sudo unbound-anchor

Unbound 서비스 시작 및 활성화

sudo systemctl --now enable unbound

Unbound 서비스 상태 확인

sudo systemctl status unbound

DNSSEC 쿼리 테스트

DNSSEC 검증이 제대로 작동하는지 확인하려면 dig 명령을 사용하여 DNS 쿼리와 함께 DNSSEC 검증을 요청할 수 있습니다.

dig @127.0.0.1 dnssec.scbyun.com A +dnssec +multi

DNSSEC 검증 실패 테스트

dig @127.0.0.1 dnssec-failed.org A +dnssec

$ dig @127.0.0.1 dnssec-failed.org A +dnssec


; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.16 <<>> @127.0.0.1 dnssec-failed.org A +dnssec
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 58375
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 4096
;; QUESTION SECTION:
;dnssec-failed.org.		IN	A

;; Query time: 1727 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: 토 10월 05 20:41:52 KST 2024
;; MSG SIZE  rcvd: 46