码迷，mamicode.com
首页 > 其他好文 > 详细

Learning of DNS

时间：2020-05-03 14:50:55      阅读：63      评论：0      收藏：0      [点我收藏+]

标签：gty   ack   poj   EDA   response   ons   info   gsm   ccs   

Headers

技术图片

Lables

Each label can be up to 63 characters long, and an entire FQDN(fully qualified domain name) is limited to at most 255 (1-byte) characters.

技术图片
技术图片

Query Format

技术图片

Answer Format

技术图片

Commands and Packets

$ dig baidu.com

; <<>> DiG 9.16.1-Ubuntu <<>> baidu.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22302
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;baidu.com.			IN	A

;; ANSWER SECTION:
baidu.com.		5	IN	A	39.156.69.79
baidu.com.		5	IN	A	220.181.38.148

;; Query time: 3 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: 日 5月 03 13:16:51 CST 2020
;; MSG SIZE  rcvd: 70

技术图片
技术图片

Simulation

$ dig +trace baidu.com

; <<>> DiG 9.16.1-Ubuntu <<>> +trace baidu.com
;; global options: +cmd
.			5	IN	NS	l.root-servers.net.
.			5	IN	NS	g.root-servers.net.
.			5	IN	NS	b.root-servers.net.
.			5	IN	NS	d.root-servers.net.
.			5	IN	NS	j.root-servers.net.
.			5	IN	NS	c.root-servers.net.
.			5	IN	NS	a.root-servers.net.
.			5	IN	NS	e.root-servers.net.
.			5	IN	NS	m.root-servers.net.
.			5	IN	NS	f.root-servers.net.
.			5	IN	NS	i.root-servers.net.
.			5	IN	NS	k.root-servers.net.
.			5	IN	NS	h.root-servers.net.
;; Received 262 bytes from 127.0.0.53#53(127.0.0.53) in 4 ms

com.			172800	IN	NS	l.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	a.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	m.gtld-servers.net.
com.			86400	IN	DS	30909 8 2 E2D3C916F6DEEAC73294E8268FB5885044A833FC5459588F4A9184CF C41A5766
com.			86400	IN	RRSIG	DS 8 1 86400 20200515170000 20200502160000 48903 . ypoqNHa/RJ1a9uTlm4QyNZ9V//oHsA2EnziYqGpmhTGWfZm1VbAriN/R cKPWdyq03XcdJl8chkHjyYFc2O7iLNiqJVTc2zUBKyBCcSY4nqftN4J+ Xhpn8i2PZaK89YoJ0u3ptUuoNQO7r7qqFoQA38TjZmVjb0xtpRsc3Qe8 NFzkHkpGG0lE87BUcxob2xxwG/w2THCu7067TbF9s5pm1NcOIgLpLrPN qAN9gal6OWpPcoj78SLrp+WG66yJLEQ1UgZafO3JaUTTUF78HCC08GL/ YfuQQSNVAJdkdYmhdSMNEPHF3YVYu2C6RWveng0HJeDfY487jKpgsmp7 0qfo8w==
;; Received 1169 bytes from 192.5.5.241#53(f.root-servers.net) in 312 ms

baidu.com.		172800	IN	NS	ns2.baidu.com.
baidu.com.		172800	IN	NS	ns3.baidu.com.
baidu.com.		172800	IN	NS	ns4.baidu.com.
baidu.com.		172800	IN	NS	ns1.baidu.com.
baidu.com.		172800	IN	NS	ns7.baidu.com.
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN NSEC3 1 1 0 - CK0Q1GIN43N1ARRC9OSM6QPQR81H5M9A NS SOA RRSIG DNSKEY NSEC3PARAM
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN RRSIG NSEC3 8 2 86400 20200509044919 20200502033919 39844 com. TuW7Gtye26JizEnQgFR2wx0iaSNeV0B+H+NGxpMvErXVC8UgY0qikZYw Q2edAoLCg1NUX+eQe6XJxCg6fxZXgmjY53nFrvS96DVAmlzHXIMGRZz9 XLb6r1dM5a9FmjWj7/Ad8CLFU4tKaARAP1eL7XAuFDIxOquFBlr2ezsz ekU8XCfOPXoFDVBREFxTbUmR09Dca+ZHK5aQmb+22qzr6A==
HPVUNU64MJQUM37BM3VJ6O2UBJCHOS00.com. 86400 IN NSEC3 1 1 0 - HPVVN3Q5E5GOQP2QFE2LEM4SVB9C0SJ6 NS DS RRSIG
HPVUNU64MJQUM37BM3VJ6O2UBJCHOS00.com. 86400 IN RRSIG NSEC3 8 2 86400 20200508042230 20200501031230 39844 com. O1F4LRXLKjRCSFcKBKFZRjVdZ7qGVDs2J3TcPWoiCg3XEfghP2I6lA8e SGhCEbmSuLlKh7bnhLuASVnN69/y+gVUtNa16eK2rNBtIrbBorwm32Dz KzMlZHdK5g5JI73IZtMaSz/oUKdqxpCgsilK0P7guLT5e9+q2pO2ROGg XrA4o3fThVbDWzRXvyXKFX1zCyBaHs+18ko17GGb8qTWDw==
;; Received 757 bytes from 192.42.93.30#53(g.gtld-servers.net) in 104 ms

baidu.com.		600	IN	A	220.181.38.148
baidu.com.		600	IN	A	39.156.69.79
baidu.com.		86400	IN	NS	ns4.baidu.com.
baidu.com.		86400	IN	NS	dns.baidu.com.
baidu.com.		86400	IN	NS	ns7.baidu.com.
baidu.com.		86400	IN	NS	ns3.baidu.com.
baidu.com.		86400	IN	NS	ns2.baidu.com.
;; Received 240 bytes from 220.181.33.31#53(ns2.baidu.com) in 12 ms


$ dig

; <<>> DiG 9.16.1-Ubuntu <<>>
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 18754
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;.				IN	NS

;; ANSWER SECTION:
.			5	IN	NS	l.root-servers.net.
.			5	IN	NS	g.root-servers.net.
.			5	IN	NS	b.root-servers.net.
.			5	IN	NS	d.root-servers.net.
.			5	IN	NS	j.root-servers.net.
.			5	IN	NS	c.root-servers.net.
.			5	IN	NS	a.root-servers.net.
.			5	IN	NS	e.root-servers.net.
.			5	IN	NS	m.root-servers.net.
.			5	IN	NS	f.root-servers.net.
.			5	IN	NS	i.root-servers.net.
.			5	IN	NS	k.root-servers.net.
.			5	IN	NS	h.root-servers.net.

;; Query time: 4 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: 日 5月 03 13:28:35 CST 2020
;; MSG SIZE  rcvd: 239

$ dig @l.root-servers.net. baidu.com

; <<>> DiG 9.16.1-Ubuntu <<>> @l.root-servers.net. baidu.com
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4979
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 13, ADDITIONAL: 27
;; WARNING: recursion requested but not available

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

;; AUTHORITY SECTION:
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.

;; ADDITIONAL SECTION:
a.gtld-servers.net.	172800	IN	A	192.5.6.30
b.gtld-servers.net.	172800	IN	A	192.33.14.30
c.gtld-servers.net.	172800	IN	A	192.26.92.30
d.gtld-servers.net.	172800	IN	A	192.31.80.30
e.gtld-servers.net.	172800	IN	A	192.12.94.30
f.gtld-servers.net.	172800	IN	A	192.35.51.30
g.gtld-servers.net.	172800	IN	A	192.42.93.30
h.gtld-servers.net.	172800	IN	A	192.54.112.30
i.gtld-servers.net.	172800	IN	A	192.43.172.30
j.gtld-servers.net.	172800	IN	A	192.48.79.30
k.gtld-servers.net.	172800	IN	A	192.52.178.30
l.gtld-servers.net.	172800	IN	A	192.41.162.30
m.gtld-servers.net.	172800	IN	A	192.55.83.30
a.gtld-servers.net.	172800	IN	AAAA	2001:503:a83e::2:30
b.gtld-servers.net.	172800	IN	AAAA	2001:503:231d::2:30
c.gtld-servers.net.	172800	IN	AAAA	2001:503:83eb::30
d.gtld-servers.net.	172800	IN	AAAA	2001:500:856e::30
e.gtld-servers.net.	172800	IN	AAAA	2001:502:1ca1::30
f.gtld-servers.net.	172800	IN	AAAA	2001:503:d414::30
g.gtld-servers.net.	172800	IN	AAAA	2001:503:eea3::30
h.gtld-servers.net.	172800	IN	AAAA	2001:502:8cc::30
i.gtld-servers.net.	172800	IN	AAAA	2001:503:39c1::30
j.gtld-servers.net.	172800	IN	AAAA	2001:502:7094::30
k.gtld-servers.net.	172800	IN	AAAA	2001:503:d2d::30
l.gtld-servers.net.	172800	IN	AAAA	2001:500:d937::30
m.gtld-servers.net.	172800	IN	AAAA	2001:501:b1f9::30

;; Query time: 8 msec
;; SERVER: 199.7.83.42#53(199.7.83.42)
;; WHEN: 日 5月 03 13:28:42 CST 2020
;; MSG SIZE  rcvd: 834

$ dig @a.gtld-servers.net. baidu.com

; <<>> DiG 9.16.1-Ubuntu <<>> @a.gtld-servers.net. baidu.com
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59027
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 5, ADDITIONAL: 6
;; WARNING: recursion requested but not available

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

;; AUTHORITY SECTION:
baidu.com.		172800	IN	NS	ns2.baidu.com.
baidu.com.		172800	IN	NS	ns3.baidu.com.
baidu.com.		172800	IN	NS	ns4.baidu.com.
baidu.com.		172800	IN	NS	ns1.baidu.com.
baidu.com.		172800	IN	NS	ns7.baidu.com.

;; ADDITIONAL SECTION:
ns2.baidu.com.		172800	IN	A	220.181.33.31
ns3.baidu.com.		172800	IN	A	112.80.248.64
ns4.baidu.com.		172800	IN	A	14.215.178.80
ns1.baidu.com.		172800	IN	A	202.108.22.220
ns7.baidu.com.		172800	IN	A	180.76.76.92

;; Query time: 292 msec
;; SERVER: 192.5.6.30#53(192.5.6.30)
;; WHEN: 日 5月 03 13:28:48 CST 2020
;; MSG SIZE  rcvd: 208

$ dig @ns2.baidu.com. baidu.com

; <<>> DiG 9.16.1-Ubuntu <<>> @ns2.baidu.com. baidu.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2415
;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 5, ADDITIONAL: 6
;; WARNING: recursion requested but not available

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

;; ANSWER SECTION:
baidu.com.		600	IN	A	39.156.69.79
baidu.com.		600	IN	A	220.181.38.148

;; AUTHORITY SECTION:
baidu.com.		86400	IN	NS	ns7.baidu.com.
baidu.com.		86400	IN	NS	ns2.baidu.com.
baidu.com.		86400	IN	NS	dns.baidu.com.
baidu.com.		86400	IN	NS	ns3.baidu.com.
baidu.com.		86400	IN	NS	ns4.baidu.com.

;; ADDITIONAL SECTION:
dns.baidu.com.		86400	IN	A	202.108.22.220
ns2.baidu.com.		86400	IN	A	220.181.33.31
ns3.baidu.com.		86400	IN	A	112.80.248.64
ns4.baidu.com.		86400	IN	A	14.215.178.80
ns7.baidu.com.		86400	IN	A	180.76.76.92

;; Query time: 8 msec
;; SERVER: 220.181.33.31#53(220.181.33.31)
;; WHEN: 日 5月 03 13:28:54 CST 2020
;; MSG SIZE  rcvd: 240

We can see the response of $ dig @ns2.baidu.com. baidu.com have aa flag set.

Learning of DNS

标签：gty   ack   poj   EDA   response   ons   info   gsm   ccs   

原文地址：https://www.cnblogs.com/ToRapture/p/12821705.html
踩
(0)
赞
(0)
   
举报
评论 一句话评论（0）
登录后才能评论！
分享档案
更多>
2021年07月29日 (22)
2021年07月28日 (40)
2021年07月27日 (32)
2021年07月26日 (79)
2021年07月23日 (29)
2021年07月22日 (30)
2021年07月21日 (42)
2021年07月20日 (16)
2021年07月19日 (90)
2021年07月16日 (35)
周排行
mamicode.com排行更多图片
更多
友情链接
兰亭集智   国之画   百度统计   站长统计   阿里云   chrome插件   新版天听网
关于我们 - 联系我们 - 留言反馈
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码！