1. Google public DNS
$ dig +tcp any qmail.jp @8.8.8.8
; <<>> DiG 9.7.3 <<>> +tcp any qmail.jp @8.8.8.8 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21821 ;; flags: qr rd ra; QUERY: 1, ANSWER: 12, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;qmail.jp. IN ANY ;; ANSWER SECTION: qmail.jp. 86400 IN SOA a.ns.qmail.jp. hostmaster.m.qmail.jp. 1306498529 16384 2048 1048576 86400 qmail.jp. 86400 IN NS a.ns.qmail.jp. qmail.jp. 86400 IN NS uz5b3p79vgf8v8yttum0fr1cbpg4tr0gdywhvwzdmb6u3hj6b8lk30.a.ns.qmail.jp. qmail.jp. 86400 IN TXT "Powered by djbdns - http://cr.yp.to/djbdns.html" qmail.jp. 86400 IN MX 0 a.mx.qmail.jp. qmail.jp. 86400 IN MX 0 abcdefghijklmnopqrstuvwxyz.mx.qmail.jp. qmail.jp. 86400 IN MX 0 abcdefghijklmnopqrstuvwxyz0.mx.qmail.jp. qmail.jp. 86400 IN MX 0 abcdefghijklmnopqrstuvwxyz1.mx.qmail.jp. qmail.jp. 86400 IN MX 0 abcdefghijklmnopqrstuvwxyz2.mx.qmail.jp. qmail.jp. 86400 IN MX 0 abcdefghijklmnopqrstuvwxyz3.mx.qmail.jp. qmail.jp. 86400 IN MX 0 abcdefghijklmnopqrstuvwxyz4.mx.qmail.jp. qmail.jp. 86400 IN A 127.0.0.128 ;; Query time: 1757 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Sat Jun 11 11:24:30 2011 ;; MSG SIZE rcvd: 523
最初だから、時間がかかる。
$ dig any qmail.jp @8.8.8.8
;; Truncated, retrying in TCP mode. ; <<>> DiG 9.7.3 <<>> any qmail.jp @8.8.8.8 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41263 ;; flags: qr rd ra; QUERY: 1, ANSWER: 12, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;qmail.jp. IN ANY ;; ANSWER SECTION: （...） ;; Query time: 67 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Sat Jun 11 11:26:14 2011 ;; MSG SIZE rcvd: 523
;; Query time: 68 msec
$ dig +tcp any qmail.jp @8.8.8.8
; <<>> DiG 9.7.3 <<>> +tcp any qmail.jp @8.8.8.8 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34523 ;; flags: qr rd ra; QUERY: 1, ANSWER: 12, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;qmail.jp. IN ANY ;; ANSWER SECTION: (省略） ;; Query time: 74 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Sat Jun 11 11:28:21 2011 ;; MSG SIZE rcvd: 523
$ time DNSCACHEIP=8.8.8.8 dnsqr any qmail.jp
255 qmail.jp: 523 bytes, 1+12+0+0 records, response, noerror query: 255 qmail.jp answer: qmail.jp 86011 SOA a.ns.qmail.jp hostmaster.m.qmail.jp 1306498529 16384 2048 1048576 86400 answer: qmail.jp 86011 NS a.ns.qmail.jp answer: qmail.jp 86011 NS uz5b3p79vgf8v8yttum0fr1cbpg4tr0gdywhvwzdmb6u3hj6b8lk30.a.ns.qmail.jp answer: qmail.jp 86011 16 /Powered\040by\040djbdns\040-\040http://cr.yp.to/djbdns.html answer: qmail.jp 86011 MX 0 a.mx.qmail.jp answer: qmail.jp 86011 MX 0 abcdefghijklmnopqrstuvwxyz.mx.qmail.jp answer: qmail.jp 86011 MX 0 abcdefghijklmnopqrstuvwxyz0.mx.qmail.jp answer: qmail.jp 86011 MX 0 abcdefghijklmnopqrstuvwxyz1.mx.qmail.jp answer: qmail.jp 86011 MX 0 abcdefghijklmnopqrstuvwxyz2.mx.qmail.jp answer: qmail.jp 86011 MX 0 abcdefghijklmnopqrstuvwxyz3.mx.qmail.jp answer: qmail.jp 86011 MX 0 abcdefghijklmnopqrstuvwxyz4.mx.qmail.jp answer: qmail.jp 86011 A 127.0.0.128 real 0m0.203s user 0m0.000s sys 0m0.000s