Packet

挖得比光速還快,可能嗎?

  • June 8, 2015

我個人喜歡dig我知道的網站。.這是我執行後在終端上看到的一件奇怪的事情dig www-contestwinners.com:-

; <<>> DiG 9.9.5-3ubuntu0.1-Ubuntu <<>> www-contestwinners.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27237
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www-contestwinners.com.        IN  A

;; ANSWER SECTION:
www-contestwinners.com. 300 IN  A   8.29.143.192

;; Query time: 40 msec
;; SERVER: 127.0.1.1#53(127.0.1.1)
;; WHEN: Sun Jun 06 20:31:40 IST 2015
;; MSG SIZE  rcvd: 67

這是荒謬的,因為我的 ISP 離我大約 200 公里,而且我正在使用 DSL 連接。考慮到數據包以光速傳播,這使得數據包從我的設備到達 ISP 伺服器的時間約為 0.6 毫秒,這並不多,但該站點的伺服器位於美國,距離我的 ISP 13000 公里使到達伺服器的時間約為 43 毫秒。因此,總往返時間約為 (43+0.6)x2= 87.2 ms。

我完全感到困惑/興奮。我想我剛剛打破了物理學的基本定律:p

**編輯:**我檢查dig www-contestwinners.com +trace了記憶體並得到:-

;; global options: +cmd
.           412410  IN  NS  i.root-servers.net.
.           412410  IN  NS  k.root-servers.net.
.           412410  IN  NS  f.root-servers.net.
.           412410  IN  NS  g.root-servers.net.
.           412410  IN  NS  e.root-servers.net.
.           412410  IN  NS  l.root-servers.net.
.           412410  IN  NS  h.root-servers.net.
.           412410  IN  NS  b.root-servers.net.
.           412410  IN  NS  a.root-servers.net.
.           412410  IN  NS  m.root-servers.net.
.           412410  IN  NS  j.root-servers.net.
.           412410  IN  NS  c.root-servers.net.
.           412410  IN  NS  d.root-servers.net.
.           518400  IN  RRSIG   NS 8 0 518400 20150618050000 20150608040000 48613 . TJF2HD0Ob5niqlCZNhlOYHvwlZmEpebgV8uFwgvRLBCQb22sq+S8Hr4d CX9S5WgzRlTxCSQ3Bi9TJNlyf221rE1K53kFbRae6/vzjR2MukvF5d8G SEWinOcJ9n7l6fTq/HoxCv/GfliY6gTPWxrc8uiABdYYOj3u3XoUmbF7 Cug=
;; Received 397 bytes from 127.0.1.1#53(127.0.1.1) in 5306 ms

com.            172800  IN  NS  a.gtld-servers.net.
com.            172800  IN  NS  b.gtld-servers.net.
com.            172800  IN  NS  c.gtld-servers.net.
com.            172800  IN  NS  d.gtld-servers.net.
com.            172800  IN  NS  e.gtld-servers.net.
com.            172800  IN  NS  f.gtld-servers.net.
com.            172800  IN  NS  g.gtld-servers.net.
com.            172800  IN  NS  h.gtld-servers.net.
com.            172800  IN  NS  i.gtld-servers.net.
com.            172800  IN  NS  j.gtld-servers.net.
com.            172800  IN  NS  k.gtld-servers.net.
com.            172800  IN  NS  l.gtld-servers.net.
com.            172800  IN  NS  m.gtld-servers.net.
com.            86400   IN  DS  30909 8 2 E2D3C916F6DEEAC73294E8268FB5885044A833FC5459588F4A9184CF C41A5766
com.            86400   IN  RRSIG   DS 8 1 86400 20150618050000 20150608040000 48613 . kSsNvyvdzfiJAxfpaRq4+bAe2JuKcDTcRnHDgGhiHNRsbcg04fHv/TNt Kkl0LuBpLcBWhBr74OkCLJxx5Q1KFkRhum2R7gHj6h5u8s4J84feqWeu fx69Defg2NWhToWDnqz0WzlUKF0nDsEyXTJDjsUeFrXu+baR3NSMLxvb zdU=
;; Received 746 bytes from 192.203.230.10#53(e.root-servers.net) in 5221 ms

www-contestwinners.com. 172800  IN  NS  dan.ns.cloudflare.com.
www-contestwinners.com. 172800  IN  NS  anna.ns.cloudflare.com.
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN NSEC3 1 1 0 - CK0QFMDQRCSRU0651QLVA1JQB21IF7UR NS SOA RRSIG DNSKEY NSEC3PARAM
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN RRSIG NSEC3 8 2 86400 20150613045314 20150606034314 33878 com. syTPVIWKgitzBOsgVgzOl7nEIsu7jhsmSXPzzLuGVUwZZC1QHc4dxmKP MkZUR+VcaY657/Knjk7Il5oOKWo8ZlTatk3+34504gWwdnbB3BShqTKS CFsWOEdw5wyf0gumuQk5GKnVR5Noo+q2+ZOxxy7LkEl0F/h7fuYj7sJA VkM=
A7FUA6LKSQCDHL6JDO7SFU649KJ6FAU5.com. 86400 IN NSEC3 1 1 0 - A7G276R35K72HBA9TE7NSAOEFTS5CADU NS DS RRSIG
A7FUA6LKSQCDHL6JDO7SFU649KJ6FAU5.com. 86400 IN RRSIG NSEC3 8 2 86400 20150614050705 20150607035705 33878 com. lIZrvjQdR4oNJTo8gW1uuzs1IuFXiqwZbI757xxBRdrYl22IDSDM4U4G i8PNVSOQ2T3ub++0VhoioWnp3aD+Uc1XmdR/jI5Z5bosIsfIrCj+CSCm ZlDShTEDsfOBLxvZ2LByGwibTHi/yuH57O+Zx3zp21RZu3xLAn2WT2aZ TrE=
;; Received 675 bytes from 192.12.94.30#53(e.gtld-servers.net) in 1539 ms

www-contestwinners.com. 300 IN  A   8.29.143.192
;; Received 67 bytes from 173.245.59.108#53(dan.ns.cloudflare.com) in 53 ms

這怎麼可能?

您查詢的域名伺服器不在美國。它離你更近了。(因此,不幸的是,您的諾貝爾獎將不得不等待。)

該跟踪輸出顯示 www-contestwinners.com 正在使用 CloudFlare 作為其 DNS 提供商。CloudFlare在世界各地運營著眾多伺服器,您的查詢被定向到最近的(或他們可以管理的最好的)伺服器。

(請注意,名稱伺服器不需要(通常也不需要)位於 Web 伺服器附近。通常名稱伺服器甚至不是由同一家公司處理。)

引用自:https://unix.stackexchange.com/questions/208272