中京大学工学部 鈴木常彦
Dec 2, 2023 DNS温泉番外編in大阪 vol.2
http://www.e-ontap.com/misc/onsenkansai2/
~% uname -a FreeBSD m1bsd 14.0-RELEASE FreeBSD 14.0-RELEASE #0 releng/14.0-n265380-f9716eee8ab4: Fri Nov 10 05:54:07 UTC 2023 root@releng1.nyi.freebsd.org:/usr/obj/usr/src/arm64.aarch64/sys/GENERIC arm64 ~% ~% dig -v DiG 9.18.19 ~% ~% unbound -V Version 1.18.0
すべての権威サーバでゾーンが適切に設定され応答しているかを確認 (NS)
~% dig @14.192.44.1 -t ns e-ontap.com +norec ; <<>> DiG 9.18.19 <<>> @14.192.44.1 -t ns e-ontap.com +norec ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27200 ;; flags: qr aa; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 2 ;; QUESTION SECTION: ;e-ontap.com. IN NS ;; ANSWER SECTION: e-ontap.com. 86400 IN NS ns.e-ontap.com. e-ontap.com. 86400 IN NS ns2.e-ontap.com. ;; ADDITIONAL SECTION: ns.e-ontap.com. 86400 IN A 14.192.44.1 ns2.e-ontap.com. 86400 IN A 49.212.106.253 ;; Query time: 19523 usec ;; SERVER: 14.192.44.1#53(14.192.44.1) (UDP) ;; WHEN: Wed Nov 29 00:25:13 JST 2023 ;; MSG SIZE rcvd: 96
応答がバッファサイズを越えると Trancation が発生 (TCP が必要)
% dig @ns.small-is-beautiful.jp -t ns small-is-beautiful.jp +norec +ignore +bufsize=512 ; <<>> DiG 9.18.16 <<>> @ns.small-is-beautiful.jp -t ns small-is-beautiful.jp +norec +ignore +bufsize=512 ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62465 ;; flags: qr aa tc; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;small-is-beautiful.jp. IN NS ;; Query time: 1 msec ;; SERVER: 150.42.6.4#53(ns.small-is-beautiful.jp) (UDP) ;; WHEN: Fri Dec 01 16:32:34 JST 2023 ;; MSG SIZE rcvd: 50
TCP での応答を確認 (with TCP)
% dig @ns.small-is-beautiful.jp -t ns small-is-beautiful.jp +norec +tcp ; <<>> DiG 9.18.16 <<>> @ns.small-is-beautiful.jp -t ns small-is-beautiful.jp +norec +tcp ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42904 ;; flags: qr aa; QUERY: 1, ANSWER: 9, AUTHORITY: 0, ADDITIONAL: 9 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;small-is-beautiful.jp. IN NS ;; ANSWER SECTION: small-is-beautiful.jp. 60 IN NS ns.small-is-beautiful.jp. small-is-beautiful.jp. 60 IN NS nsa.dns.jp. small-is-beautiful.jp. 60 IN NS a01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. small-is-beautiful.jp. 60 IN NS b01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. small-is-beautiful.jp. 60 IN NS c01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. small-is-beautiful.jp. 60 IN NS d01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. small-is-beautiful.jp. 60 IN NS e01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. small-is-beautiful.jp. 60 IN NS f01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. small-is-beautiful.jp. 60 IN NS g01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. ;; ADDITIONAL SECTION: ns.small-is-beautiful.jp. 60 IN A 150.42.6.4 a01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. 60 IN A 150.42.6.4 b01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. 60 IN A 150.42.6.4 c01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. 60 IN A 150.42.6.4 d01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. 60 IN A 150.42.6.4 e01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. 60 IN A 150.42.6.4 f01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. 60 IN A 150.42.6.4 g01234567890123456789012345678901234567890123456789012345678901.small-is-beautiful.jp. 60 IN A 150.42.6.4 ;; Query time: 1 msec ;; SERVER: 150.42.6.4#53(ns.small-is-beautiful.jp) (TCP) ;; WHEN: Fri Dec 01 16:38:06 JST 2023 ;; MSG SIZE rcvd: 763
すべての権威サーバでゾーンが適切に設定され応答しているかを確認 (SOA)
~% dig @14.192.44.1 -t soa e-ontap.com +norec ; <<>> DiG 9.18.19 <<>> @14.192.44.1 -t soa e-ontap.com +norec ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9921 ;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;e-ontap.com. IN SOA ;; ANSWER SECTION: e-ontap.com. 86400 IN SOA ns.e-ontap.com. tss.e-ontap.com. ( 2023112901 ; serial 3600 ; refresh (1 hour) 1800 ; retry (30 minutes) 604800 ; expire (1 week) 600 ; minimum (10 minutes) ) ;; AUTHORITY SECTION: e-ontap.com. 86400 IN NS ns.e-ontap.com. e-ontap.com. 86400 IN NS ns2.e-ontap.com. ;; ADDITIONAL SECTION: ns.e-ontap.com. 86400 IN A 14.192.44.1 ns2.e-ontap.com. 86400 IN A 49.212.106.253 ;; Query time: 11213 usec ;; SERVER: 14.192.44.1#53(14.192.44.1) (UDP) ;; WHEN: Wed Nov 29 00:25:50 JST 2023 ;; MSG SIZE rcvd: 136
委譲元サーバが適切に委譲応答しているかを確認
~% dig @a.gtld-servers.net e-ontap.com +norec
; <<>> DiG 9.18.19 <<>> @a.gtld-servers.net e-ontap.com +norec
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3976
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 3
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; NSID: 6e 6e 6e 31 2d 6a 70 74 79 6f 2d 31 61 ("nnn1-jptyo-1a")
;; QUESTION SECTION:
;e-ontap.com. IN A
;; AUTHORITY SECTION:
e-ontap.com. 172800 IN NS ns.e-ontap.com.
e-ontap.com. 172800 IN NS ns2.e-ontap.com.
;; ADDITIONAL SECTION:
ns.e-ontap.com. 172800 IN A 14.192.44.1
ns2.e-ontap.com. 172800 IN A 49.212.106.253
;; Query time: 20266 usec
;; SERVER: 192.5.6.30#53(a.gtld-servers.net) (UDP)
;; WHEN: Wed Nov 29 00:42:51 JST 2023
;; MSG SIZE rcvd: 124
委譲元サーバが適切に委譲応答しているかを確認 (jp は RFC 9471 違反では?)
(bufsizeの境界は変化するので要調整)
% dig internat.jp @a.dns.jp +dnssec +ignore +norec +bufsize=580
; <<>> DiG 9.18.16 <<>> internat.jp @a.dns.jp +dnssec +ignore +norec +bufsize=580
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39675
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 5, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 1232
; NSID: 61 32 32 2e 6f 73 61 ("a22.osa")
; COOKIE: 5f5efd628dcbc6089bfcc1a06569904dc4afe4df073d9d18 (good)
;; QUESTION SECTION:
;internat.jp. IN A
;; AUTHORITY SECTION:
internat.jp. 86400 IN NS ns.internat.jp.
B9CCVLLHT15JM5HET57BQ8MLBAAKPI82.jp. 900 IN NSEC3 1 1 0 - (
B9GCLVHJOFB3318PIQ42MAJLDH459SFM
NS SOA RRSIG DNSKEY NSEC3PARAM )
B9CCVLLHT15JM5HET57BQ8MLBAAKPI82.jp. 900 IN RRSIG NSEC3 8 2 900 (
20231225174503 20231125174503 36861 jp.
GvHN2g6bsLGK/KIIpfT2mkTRqZZJTC3PAS9gYiICLN6K
NK6Vz6Q5RxmE2I2q/m2jAVLyQ5cTXfKIwfx794upGrmA
5UM29+Tmo5C94qwP73MR0qCb0FaiToax6V56eS5hPI7n
9A2rk3cius7jtdkmbLRvmH0dryAxrHbBLVyH+go= )
277VGC2Q12PVBCHN4U8SPBSL3CRT0OJL.jp. 900 IN NSEC3 1 1 0 - (
27CMEBITE9GA8MM87CBR464DL0S5VE69
TXT RRSIG )
277VGC2Q12PVBCHN4U8SPBSL3CRT0OJL.jp. 900 IN RRSIG NSEC3 8 2 900 (
20231225174503 20231125174503 36861 jp.
ZY8ne1L09yXnkYqCLUZqH1QSF9avCY63eE3sFMeTbmfw
GEa3yw4kPN9N03gRLSfqt+K1HqkCF9D9djXJlaX2X1eF
VnYToXK3gLZfOzF4kRENznZchQKhqXV7Nrhey9bQly2k
o2CfexywZoJwjD8JDUkp+Iy4OJi7fk+DIkXdqK0= )
(Additional がない)
;; Query time: 5 msec
;; SERVER: 203.119.1.1#53(a.dns.jp) (UDP)
;; WHEN: Fri Dec 01 16:50:37 JST 2023
;; MSG SIZE rcvd: 579
RFC 9471: If message size constraints prevent the inclusion of all glue records for in-domain name servers over the chosen transport, the server MUST set the TC (Truncated) flag to inform the client that the response is incomplete and that the client SHOULD use another transport to retrieve the full response.
ADDITIONAL の数は EDNS の分 +1, バッファサイズ (DNS Flag DAY 2020 の推奨は 1232) など
~% dig @ns.mufj.jp -t soa mufj.jp +norec +noall +comm +qr
;; Sending:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4102
;; flags: ad; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 1232
; NSID:
; COOKIE: 7e65ac204aac1614
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4102
;; flags: qr aa; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 3
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 1232
; NSID: de ca fe ("...")
; COOKIE: 7e65ac204aac1614010000006566f643050db3e799d69d93 (good)
Google Public DNS の EDNS バッファサイズは 512
% dig @8.8.8.8 www.mufj.jp +rec +dnssec +qr
; <<>> DiG 9.18.16 <<>> @8.8.8.8 www.mufj.jp +rec +dnssec +qr
; (1 server found)
;; global options: +cmd
;; Sending:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31155
;; flags: rd ad; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 1232
; NSID:
; COOKIE: 43050d37a9ddb3c2
;; QUESTION SECTION:
;www.mufj.jp. IN A
;; QUERY SIZE: 56
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31155
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 512
; NSID: 67 70 64 6e 73 2d 6b 69 78 ("gpdns-kix")
;; QUESTION SECTION:
;www.mufj.jp. IN A
;; ANSWER SECTION:
www.mufj.jp. 3582 IN A 49.212.171.172
www.mufj.jp. 3582 IN RRSIG A 13 3 3600 (
20371231000000 20230907054100 17603 mufj.jp.
VuoBKCZ1rKUjatrOC2jLjtjHZHHewWgEgUexVQl3XkNy
tHZ6T3dSGdWODQThBgZeggbm2h69FabFkTU9NQkHFw== )
;; Query time: 16425 usec
;; SERVER: 8.8.8.8#53(8.8.8.8) (UDP)
;; WHEN: Fri Dec 01 10:35:32 JST 2023
;; MSG SIZE rcvd: 172
Unbound 1.19 (default), dnssec-failed.mufj.jp
% dig dnssec-failed.mufj.jp +rec +dnssec ; <<>> DiG 9.18.16 <<>> dnssec-failed.mufj.jp +rec +dnssec ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 62054 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags: do; udp: 512 ; EDE: 9 (DNSKEY Missing): (validation failure: No DNSKEY record from 150.42.6.2 for key dnssec-failed.mufj.jp. while building chain of trust) ;; QUESTION SECTION: ;dnssec-failed.mufj.jp. IN A ;; Query time: 117 msec ;; SERVER: 127.0.0.2#53(127.0.0.2) (UDP) ;; WHEN: Fri Dec 01 15:29:16 JST 2023 ;; MSG SIZE rcvd: 199
Unbound 1.19 (default), dnssec-failed.mufj.jp, checking disabled
% dig dnssec-failed.mufj.jp +rec +cd ; <<>> DiG 9.18.16 <<>> dnssec-failed.mufj.jp +rec +cd ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30202 ;; flags: qr rd ra cd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ; EDE: 9 (DNSKEY Missing): (validation failure: No DNSKEY record from 150.42.6.2 for key dnssec-failed.mufj.jp. while building chain of trust) ;; QUESTION SECTION: ;dnssec-failed.mufj.jp. IN A ;; ANSWER SECTION: dnssec-failed.mufj.jp. 51 IN A 150.42.6.5 ;; AUTHORITY SECTION: dnssec-failed.mufj.jp. 591 IN NS ns.dnssec-failed.mufj.jp. ;; ADDITIONAL SECTION: ns.dnssec-failed.mufj.jp. 591 IN A 150.42.6.2 ;; Query time: 0 msec ;; SERVER: 127.0.0.2#53(127.0.0.2) (UDP) ;; WHEN: Fri Dec 01 15:45:49 JST 2023 ;; MSG SIZE rcvd: 248
% dig tkix.net +trace +nodnssec ; <<>> DiG 9.18.19 <<>> tkix.net +trace +nodnssec ;; global options: +cmd . 84961 IN NS i.root-servers.net. . 84961 IN NS j.root-servers.net. . 84961 IN NS k.root-servers.net. . 84961 IN NS l.root-servers.net. . 84961 IN NS m.root-servers.net. . 84961 IN NS a.root-servers.net. . 84961 IN NS b.root-servers.net. . 84961 IN NS c.root-servers.net. . 84961 IN NS d.root-servers.net. . 84961 IN NS e.root-servers.net. . 84961 IN NS f.root-servers.net. . 84961 IN NS g.root-servers.net. . 84961 IN NS h.root-servers.net. ;; Received 811 bytes from 127.0.0.2#53(127.0.0.2) in 0 ms net. 172800 IN NS a.gtld-servers.net. net. 172800 IN NS b.gtld-servers.net. net. 172800 IN NS c.gtld-servers.net. net. 172800 IN NS d.gtld-servers.net. net. 172800 IN NS e.gtld-servers.net. net. 172800 IN NS f.gtld-servers.net. net. 172800 IN NS g.gtld-servers.net. net. 172800 IN NS h.gtld-servers.net. net. 172800 IN NS i.gtld-servers.net. net. 172800 IN NS j.gtld-servers.net. net. 172800 IN NS k.gtld-servers.net. net. 172800 IN NS l.gtld-servers.net. net. 172800 IN NS m.gtld-servers.net. ;; Received 830 bytes from 192.58.128.30#53(j.root-servers.net) in 22 ms tkix.net. 172800 IN NS ns.tkix.net. tkix.net. 172800 IN NS fake.spam18.net. tkix.net. 172800 IN NS fake2.spam18.net. couldn't get address for 'fake.spam18.net': failure couldn't get address for 'fake2.spam18.net': failure ;; Received 148 bytes from 192.31.80.30#53(d.gtld-servers.net) in 24 ms tkix.net. 300 IN SOA ns.tkix.net. hostmaster.e-ontap.com. 2019102401 3600 1800 604800 300 ;; Received 87 bytes from 14.192.44.1#53(ns.tkix.net) in 10 ms
% dig @a.gtld-servers.net tkix.net +noall +auth +add +norec tkix.net. 172800 IN NS ns.tkix.net. tkix.net. 172800 IN NS fake.spam18.net. tkix.net. 172800 IN NS fake2.spam18.net. ns.tkix.net. 172800 IN A 150.42.6.4 fake.spam18.net. 172800 IN A 14.192.44.1 fake2.spam18.net. 172800 IN A 14.192.44.1 % % dig @1.1.1.1 -t txt tkix.net +rec +short "This_zone_is_authoritative." % dig @1.1.1.1 -t a ns.tkix.net +rec +short 150.42.6.4 % % dig @8.8.8.8 -t txt tkix.net +rec +short "Do_you_believe_this_zone?" % dig @8.8.8.8 -t a ns.tkix.net +rec +short 14.192.44.1
% grep www.example.com /etc/hosts 127.0.0.1 localhost www.example.com
% dig www.example.com +rec +noall +ans www.example.com. 86253 IN A 93.184.216.34 www.example.com. 86253 IN RRSIG A 13 3 86400 ( 20231209033139 20231118101641 46981 example.com. uXV+NP7ZgIms4Srumsn4M2Q5hUABAd2nG5N3thnT9QMS 2mZDgIZzWDRDPNbbNhe9/3m1HQyboAipxHCuv3CjBw== )
% ping -c 1 www.example.com PING localhost (127.0.0.1): 56 data bytes 64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.044 ms --- localhost ping statistics --- 1 packets transmitted, 1 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 0.044/0.044/0.044/nan ms
重要なもの
非再帰問い合わせによる適切な設定確認のため
勝手に TCP フォールバックしないようにして TC ビットを確認しよう。
検索失敗に気づこう。(Query time に疑問を持ったことはありませんか?)
DNS Day 2020 の推奨値
これらを ~/.digrc に記述
必要・好みに応じて
DNSSEC を利用している環境への影響を確認
環境に応じて (デフォルト値 5 は気長)
負荷分散環境の確認に有用 (実装の違いが出る場合がある)
高速な環境向け (東京に住んでいる人や社内のサーバを調査する人など)
以下のような alias を設定しておくと便利
alias digroot="dig @m.root-servers.net" alias digcom="dig @a.gtld-servers.net" alias digjp="dig @z.dns.jp"
再帰検索要求の際に+rec を付けるのが面倒な人は
alias digr="dig +rec"
私は ~/bin/dig に以下のスクリプトを置いています
#!/bin/sh
TIME=`echo | tai64n`
dig $@ |tee ~/histdig/$TIME
( ~/histdig に @40000000656679ef1acf848c 等のファイル名のアーカイブが残る)
dig の表示ごちゃごちゃして見づらくないですか?
dig +rec と dig +norec の使い分け間違えそうじゃないですか?
djbdns-tools 使ってみませんか?
% dnsq ns e-ontap.com 14.192.44.1 2 e-ontap.com: 96 bytes, 1+2+0+2 records, response, authoritative, noerror query: 2 e-ontap.com answer: e-ontap.com 86400 NS ns.e-ontap.com answer: e-ontap.com 86400 NS ns2.e-ontap.com additional: ns.e-ontap.com 86400 A 14.192.44.1 additional: ns2.e-ontap.com 86400 A 49.212.106.253 % % dnsqr ns e-ontap.com 2 e-ontap.com: 96 bytes, 1+2+0+2 records, response, noerror query: 2 e-ontap.com answer: e-ontap.com 43013 NS ns2.e-ontap.com answer: e-ontap.com 43013 NS ns.e-ontap.com additional: ns.e-ontap.com 43013 A 14.192.44.1 additional: ns2.e-ontap.com 43013 A 49.212.106.253
% dnsq ptr 59.6.42.150.in-addr.arpa a.in-addr-servers.arpa 12 59.6.42.150.in-addr.arpa: 209 bytes, 1+0+5+0 records, response, noerror query: 12 59.6.42.150.in-addr.arpa authority: 150.in-addr.arpa 86400 NS apnic1.dnsnode.net authority: 150.in-addr.arpa 86400 NS ns3.lacnic.net authority: 150.in-addr.arpa 86400 NS apnic.authdns.ripe.net authority: 150.in-addr.arpa 86400 NS rirns.arin.net authority: 150.in-addr.arpa 86400 NS ns2.apnic.net % % dnsq ptr 59.6.42.150.in-addr.arpa ns2.apnic.net 12 59.6.42.150.in-addr.arpa: 119 bytes, 1+0+2+0 records, response, noerror query: 12 59.6.42.150.in-addr.arpa authority: 42.150.in-addr.arpa 86400 NS ns1.hs.ctc.jp authority: 42.150.in-addr.arpa 86400 NS dns-x.sinet.ad.jp % % dnsq ptr 59.6.42.150.in-addr.arpa dns-x.sinet.ad.jp 12 59.6.42.150.in-addr.arpa: 147 bytes, 1+1+2+0 records, response, authoritative, noerror query: 12 59.6.42.150.in-addr.arpa answer: 59.6.42.150.in-addr.arpa 86400 CNAME 59.0-63.6.42.150.in-addr.arpa authority: 0-63.6.42.150.in-addr.arpa 86400 NS ns4.suzuki.sist.chukyo-u.ac.jp authority: 0-63.6.42.150.in-addr.arpa 86400 NS ns3.suzuki.sist.chukyo-u.ac.jp % % dnsq ptr 59.0-63.6.42.150.in-addr.arpa ns3.suzuki.sist.chukyo-u.ac.jp 12 59.0-63.6.42.150.in-addr.arpa: 103 bytes, 1+1+1+1 records, response, authoritative, noerror query: 12 59.0-63.6.42.150.in-addr.arpa answer: 59.0-63.6.42.150.in-addr.arpa 86400 CNAME 59.48-61.0-63.6.42.150.in-addr.arpa authority: 48-61.0-63.6.42.150.in-addr.arpa 86400 NS ns.48-61.0-63.6.42.150.in-addr.arpa additional: ns.48-61.0-63.6.42.150.in-addr.arpa 86400 A 150.42.6.53 % % dnsq ptr 59.48-61.0-63.6.42.150.in-addr.arpa 150.42.6.53 12 59.48-61.0-63.6.42.150.in-addr.arpa: 169 bytes, 1+4+1+1 records, response, authoritative, noerror query: 12 59.48-61.0-63.6.42.150.in-addr.arpa answer: 59.48-61.0-63.6.42.150.in-addr.arpa 160 PTR wiki.convivial.ne.jp answer: 59.48-61.0-63.6.42.150.in-addr.arpa 160 PTR mm.convivial.ne.jp answer: 59.48-61.0-63.6.42.150.in-addr.arpa 160 PTR www.convivial.ne.jp answer: 59.48-61.0-63.6.42.150.in-addr.arpa 160 PTR convivial.ne.jp authority: 48-61.0-63.6.42.150.in-addr.arpa 140 NS ns.48-61.0-63.6.42.150.in-addr.arpa additional: ns.48-61.0-63.6.42.150.in-addr.arpa 140 A 150.42.6.53