RESOLVED.CONF(5) resolved.conf RESOLVED.CONF(5) (NAME) resolved.conf - (systemd-resolved) (SYNOPSIS) /etc/systemd/resolved.conf /run/systemd/resolved.conf /usr/local/lib/systemd/resolved.conf /usr/lib/systemd/resolved.conf /etc/systemd/resolved.conf.d/*.conf /run/systemd/resolved.conf.d/*.conf /usr/local/lib/systemd/resolved.conf.d/*.conf /usr/lib/systemd/resolved.conf.d/*.conf (DESCRIPTION) DNS LLMNR . (CONFIGURATION DIRECTORIES AND PRECEDENCE) . : /etc/systemd/ /run/systemd/ /usr/local/lib/systemd/ [1] /usr/lib/systemd/. (vendor) . (drop-in) . ( /etc/ /usr/ ) (drop-in) . (drop-in) /usr/lib/systemd/*.conf.d/ /usr/local/lib/systemd/*.conf.d/ /etc/systemd/*.conf.d/ . (override) . *.conf.d/ (lexicographic) . . (drop-in) /usr/ . /etc/ . . . . . 10-40 /usr/ 60-90 /etc/ /run/ . (symlink) /dev/null /etc/ . (OPTIONS) [Resolve] : DNS= IPv4 IPv6 DNS . ":" "%" (SNI) "#" . IPv6 () . : "111.222.333.444:9953%ifname#example.com" IPv4 "[1111:2222::3333]:9953%ifname#example.com" IPv6. DNS DNS DNS (per-link) systemd-networkd.service(8) . DNS /etc/resolv.conf . . 213. FallbackDNS= IPv4 IPv6 DNS (fallback). DNS= . DNS systemd-networkd.service(8) DNS= /etc/resolv.conf . DNS . DNS . 216. Domains= "~" . . "~" ( ) (FQDN) . << >> . /etc/resolv.conf search . "~" << ->> (route-only domains) . ( - "~") DNS . DNS . DNS= ( ) DHCP . DNS - . "~." ( "~" - "." DNS DNS ) DNS . - "Protocols and Routing" systemd-resolved.service(8) . MulticastDNS "local" DNS (unicast) . IANA MulticastDNS DNS . DNS MulticastDNS . 229. LLMNR= "resolve" . - (LLMNR - RFC 4795[2]) . true LLMNR . false . "resolve" . systemd-networkd.service(8) LLMNR . LLMNR . 216. MulticastDNS= "resolve" . DNS (mDNS - RFC 6762[3]) . true DNS . false . "resolve" . systemd-networkd.service(8) DNS . DNS . 234. DNSSEC= "allow-downgrade" . true DNS DNSSEC ( LLMNR DNS ). . DNS DNSSEC . DNS DNSSEC . "allow-downgrade" DNSSEC DNSSEC DNSSEC . DNSSEC << >> (downgrade) DNS DNSSEC DNSSEC . false DNS DNSSEC . DNSSEC DNS DNS . DNSSEC << >> (trust anchors) . dnssec-trust-anchors.d(5) . . DNSSEC . DNSSEC= true . DNSSEC= "allow-downgrade" DNSSEC . DNS DNSSEC ( DNS DNS DNSSEC ). DNS . DNS DNSSEC DNSSEC= true . DNSSEC= "allow-downgrade" . DNSSEC systemd-networkd.service(8) DNSSEC . DNS ( ) DNSSEC . DNS . DNS - (Site- private DNS zones) DNSSEC ( ) ( ) . "allow-downgrade" DNS - (TLDs) DNS . . "no" . 229. DNSOverTLS= "opportunistic" . true . DNS DNS-over-TLS . DNS= "address#server_name" (SNI) TLS . IP . DNS DNS-over-TLS DNS . "opportunistic" DNS DNS-over-TLS . DNS TLS DNS-over-TLS . DNS-over-TLS << >> (downgrade) DNS-over-TLS . false DNS UDP . DNS-over-TLS DNS . "opportunistic" << >> (man-in-the-middle) . DNSOverTLS= systemd-networkd.service(8) DNSOverTLS= . DNS ( ) DNSOverTLS= . DNS . "no" . 239. Cache= "no-negative" . "yes" () . (caching) DNSSEC . "no-negative" . DNS (host- local) . CacheFromLocalhost= . 231. CacheFromLocalhost= . "no" () IP ( 127.0.0.1 ::1) . 248. DNSCacheSize=, MulticastDNSCacheSize=, LLMNRCacheSize= . DNS DNS DNS (mDNS) - (LLMNR) (per-scope) . 4096 . 16777216 (2^24) . 0 . Cache= "yes" "no-negative" . Cache=no . DNS . DNSCacheSize= MulticastDNSCacheSize= . systemd-resolved (memory pressure) . DNS . CacheFromLocalhost= . 261. DNSStubListener= "udp" "tcp" . "udp" DNS (stub resolver) UDP 127.0.0.53 127.0.0.54 53 . "tcp" TCP . "yes" () UDP TCP . "no" . DNS 127.0.0.53 LLMNR/MulticastDNS . DNS 127.0.0.54 <<>> (proxy) DNS DNS DNSSEC LLMNR/MulticastDNS . ( DNS- over-TLS .) DNS DNS . 232. RefuseRecordTypes= DNS . . . . : RefuseRecordTypes=AAAA SRV TXT AAAA ( SRV TXT ) IPv6 "sysctl -w net.ipv6.conf.all.disable_ipv6=1" . 258. DNSStubListenerExtra= IPv4 IPv6 . ("udp" "tcp") ":" . UDP TCP . ":" . IPv6 () . 53 . DNS DNSStubListener= . . . . : DNSStubListenerExtra=192.168.10.10 DNSStubListenerExtra=2001:db8:0:f102::10 DNSStubListenerExtra=192.168.10.11:9953 DNSStubListenerExtra=[2001:db8:0:f102::11]:9953 DNSStubListenerExtra=tcp:192.168.10.12 DNSStubListenerExtra=udp:2001:db8:0:f102::12 DNSStubListenerExtra=tcp:192.168.10.13:9953 DNSStubListenerExtra=udp:[2001:db8:0:f102::13]:9953 247. ReadEtcHosts= . "yes" () systemd-resolved /etc/hosts DNS . 240. ReadStaticRecords= . "yes" () systemd-resolved /etc/systemd/resolve/static.d/*.rr /run/systemd/resolve/static.d/*.rr /usr/local/lib/systemd/resolve/static.d/*.rr /usr/lib/systemd/resolve/static.d/*.rr DNS . ReadEtcHosts= DNS A/AAAA/PTR . systemd.rr(5) . ReadEtcHosts= : /etc/hosts . 261. ResolveUnicastSingleLabel= . false () systemd-resolved A AAAA DNS . ( Domains= ) LLMNR /etc/hosts . true DNS . DNS . IAB[4] . 246. StaleRetentionSec=SECONDS DNS (TTL) . (stale) . DNS TTL . DNS . systemd-resolved(8) DNS DNS . NXDOMAIN . DNS . systemd-resolved DNS . . 254. (SEE ALSO) systemd(1) systemd-resolved.service(8) systemd- networkd.service(8) dnssec-trust-anchors.d(5) systemd.rr(5) resolv.conf(5) (NOTES) 1. . /usr/local/ . 2. RFC 4795 https://tools.ietf.org/html/rfc4795 3. RFC 6762 https://tools.ietf.org/html/rfc6762 4. IAB https://www.iab.org/documents/correspondence-reports- documents/2013-2/iab-statement-dotless-domains-considered-harmful systemd 261.2 RESOLVED.CONF(5)