Linux/UNIX DNS查找命令

原文参考 http://www.cyberciti.biz/faq/unix-linux-dns-lookup-command/

两条命令可帮你解决DNS服务器和域名解析的问题：host 和 dig 。

host命令的基本格式：

host example.com
host -t TYPE example.com
host -t a example.com

host例子（美元符号 $ 表示 shell提示符）

$ host -t a cyberciti.biz
cyberciti.biz has address 75.126.153.206

$ host -t mx cyberciti.biz
cyberciti.biz mail is handled by 2 CYBERCITI.BIZ.S9A2.PSMTP.com.
cyberciti.biz mail is handled by 3 CYBERCITI.BIZ.S9B1.PSMTP.com.
cyberciti.biz mail is handled by 4 CYBERCITI.BIZ.S9B2.PSMTP.com.
cyberciti.biz mail is handled by 1 CYBERCITI.BIZ.S9A1.PSMTP.com.

$ host -t ns cyberciti.biz
cyberciti.biz name server ns2.nixcraft.net.
cyberciti.biz name server ns1.nixcraft.net.
cyberciti.biz name server ns5.nixcraft.net.
cyberciti.biz name server ns4.nixcraft.net.

$ host -t txt cyberciti.biz
cyberciti.biz descriptive text "v=spf1 a mx ip4:74.86.48.99 ip4:74.86.48.98 ip4:74.86.48.102 ip4:74.86.48.101 ip4:74.86.48.100 ip4:72.26.218.170 ip4:93.89.92.12 ip4:180.92.186.178 include:_spf.google.com ~all"

$ host -t cname files.cyberciti.biz
files.cyberciti.biz is an alias for files.cyberciti.biz.edgesuite.net.

$ host -t soa cyberciti.biz
cyberciti.biz has SOA record ns1.nixcraft.net. vivek.nixcraft.com. 2008072353 10800 3600 604800 3600

可在命令的尾部加上域名服务器地址，以查询特定的DNS服务器，比如从 ns2.nixcraft.net 服务器查询 cyberciti.biz 的记录

$ host cyberciti.biz ns2.nixcraft.net
Using domain server:
Name: ns2.nixcraft.net
Address: 75.126.168.152#53
Aliases:

cyberciti.biz has address 75.126.153.206
cyberciti.biz has IPv6 address 2607:f0d0:1002:51::4
cyberciti.biz mail is handled by 3 CYBERCITI.BIZ.S9B1.PSMTP.com.
cyberciti.biz mail is handled by 4 CYBERCITI.BIZ.S9B2.PSMTP.com.
cyberciti.biz mail is handled by 1 CYBERCITI.BIZ.S9A1.PSMTP.com.
cyberciti.biz mail is handled by 2 CYBERCITI.BIZ.S9A2.PSMTP.com.

可以查询关于某个域的所有信息，

$ host -a cyberciti.biz

或者

$ host -t any cyberciti.biz

输出为

Trying "cyberciti.biz"
;; Truncated, retrying in TCP mode.
Trying "cyberciti.biz"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34079
;; flags: qr rd ra; QUERY: 1, ANSWER: 14, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;cyberciti.biz. IN ANY

;; ANSWER SECTION:
cyberciti.biz. 3423 IN AAAA 2607:f0d0:1002:51::4
cyberciti.biz. 3600 IN SOA ns1.nixcraft.net. vivek.nixcraft.com. 2008072353 10800 3600 604800 3600
cyberciti.biz. 3600 IN TXT "v=spf1 a mx ip4:74.86.48.99 ip4:74.86.48.98 ip4:74.86.48.102 ip4:74.86.48.101 ip4:74.86.48.100 ip4:72.26.218.170 ip4:93.89.92.12 ip4:180.92.186.178 include:_spf.google.com ~all"
cyberciti.biz. 3600 IN MX 2 CYBERCITI.BIZ.S9A2.PSMTP.com.
cyberciti.biz. 3600 IN MX 3 CYBERCITI.BIZ.S9B1.PSMTP.com.
cyberciti.biz. 3600 IN MX 4 CYBERCITI.BIZ.S9B2.PSMTP.com.
cyberciti.biz. 3600 IN MX 1 CYBERCITI.BIZ.S9A1.PSMTP.com.
cyberciti.biz. 2805 IN A 75.126.153.206
cyberciti.biz. 3423 IN NS ns2.nixcraft.net.
cyberciti.biz. 3423 IN NS ns5.nixcraft.net.
cyberciti.biz. 3423 IN NS ns1.nixcraft.net.
cyberciti.biz. 3423 IN NS ns4.nixcraft.net.
cyberciti.biz. 84092 IN RRSIG NSEC 8 2 86400 20101125013720 20101026010313 50568 biz. OjDv09mccTZR2bYCl4D57QcnNEkBq6bNEa20ExsI6NC2sI9pmiKLnq+w UnCYxWMnkMi7WNXwIhhUWtNhV48X3wJGj1Mufrhq8MnO25JIcRE6UJF2 y12TTZHHE0UJV6HSkw1sac3XlZKXLi/oSvE/IXTsdj2SckPh+pMlaieQ jAA=
cyberciti.biz. 84092 IN NSEC CYBERCITIZEN.biz. NS RRSIG NSEC

Received 749 bytes from 192.168.1.254#53 in 0.1 ms

可以使用ipv6查询

$ host -6 cyberciti.biz
$ host -6 -a cyberciti.biz
$ host -6 cyberciti.biz ns1.nixcraft.net
$ host -6 -t ns cyberciti.biz ns3.nixcraft.net

输出为

Using domain server:
Name: ns3.nixcraft.net
Address: 2001:48c8:10:1::2#53
Aliases:

cyberciti.biz name server ns2.nixcraft.net.
cyberciti.biz name server ns4.nixcraft.net.
cyberciti.biz name server ns5.nixcraft.net.
cyberciti.biz name server ns1.nixcraft.net.

反向地址解析的格式为
$ host {IP-Address-Here}

比如

$ host 75.126.153.206
206.153.126.75.in-addr.arpa domain name pointer www.cyberciti.biz.

得到TTL信息的格式是
$ host -v -t {TYPE} {example.com}

比如
$ host -v -t a cyberciti.biz
Trying "cyberciti.biz"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 17431
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 7

;; QUESTION SECTION:
;cyberciti.biz. IN A

;; ANSWER SECTION:
cyberciti.biz. 1866 IN A 75.126.153.206

;; AUTHORITY SECTION:
cyberciti.biz. 3850 IN NS NS1.NIXCRAFT.NET.
cyberciti.biz. 3850 IN NS NS4.NIXCRAFT.NET.
cyberciti.biz. 3850 IN NS NS5.NIXCRAFT.NET.
cyberciti.biz. 3850 IN NS NS2.NIXCRAFT.NET.

;; ADDITIONAL SECTION:
NS1.NIXCRAFT.NET. 85669 IN A 72.26.218.170
NS1.NIXCRAFT.NET. 85689 IN AAAA 2001:48c8:7::2
NS2.NIXCRAFT.NET. 85669 IN A 75.126.168.152
NS2.NIXCRAFT.NET. 85669 IN AAAA 2607:f0d0:1002:51::3
NS4.NIXCRAFT.NET. 85669 IN A 93.89.92.12
NS4.NIXCRAFT.NET. 85669 IN AAAA 2a01:348:0:15:5d59:50c:0:1
NS5.NIXCRAFT.NET. 85669 IN AAAA 2001:48c8:10:1::2

Received 291 bytes from 10.0.80.11#53 in 2 ms

dig命令比host功能更多，典型用法

dig @{ns1.example.com} {example.com}
dig @{ns1.example.com} {example.com} {TYPE}
dig cyberciti.biz a
dig cyberciti.biz mx
dig cyberciti.biz ns
dig cyberciti.biz txt
dig @ns1.nixcraft.net cyberciti.biz a

trace选项可跟踪从根域开始的递归查询过程，比如

$dig +trace cyberciti.biz
<<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> +trace cyberciti.biz
;; global options: printcmd
. 41219 IN NS b.root-servers.net.
. 41219 IN NS e.root-servers.net.
. 41219 IN NS i.root-servers.net.
. 41219 IN NS d.root-servers.net.
. 41219 IN NS g.root-servers.net.
. 41219 IN NS k.root-servers.net.
. 41219 IN NS l.root-servers.net.
. 41219 IN NS c.root-servers.net.
. 41219 IN NS m.root-servers.net.
. 41219 IN NS a.root-servers.net.
. 41219 IN NS h.root-servers.net.
. 41219 IN NS j.root-servers.net.
. 41219 IN NS f.root-servers.net.
;; Received 436 bytes from 10.0.80.11#53(10.0.80.11) in 2 ms

biz. 172800 IN NS h.gtld.biz.
biz. 172800 IN NS c.gtld.biz.
biz. 172800 IN NS e.gtld.biz.
biz. 172800 IN NS b.gtld.biz.
biz. 172800 IN NS g.gtld.biz.
biz. 172800 IN NS a.gtld.biz.
biz. 172800 IN NS f.gtld.biz.
;; Received 316 bytes from 192.228.79.201#53(b.root-servers.net) in 34 ms

cyberciti.biz. 7200 IN NS NS5.NIXCRAFT.NET.
cyberciti.biz. 7200 IN NS NS1.NIXCRAFT.NET.
cyberciti.biz. 7200 IN NS NS2.NIXCRAFT.NET.
cyberciti.biz. 7200 IN NS NS4.NIXCRAFT.NET.
;; Received 115 bytes from 2001:503:8028:ffff:ffff:ffff:ffff:ff7e#53(h.gtld.biz) in 23 ms

cyberciti.biz. 3600 IN A 75.126.153.206
cyberciti.biz. 3600 IN NS ns4.nixcraft.net.
cyberciti.biz. 3600 IN NS ns5.nixcraft.net.
cyberciti.biz. 3600 IN NS ns1.nixcraft.net.
cyberciti.biz. 3600 IN NS ns2.nixcraft.net.
;; Received 307 bytes from 2001:48c8:10:1::2#53(NS5.NIXCRAFT.NET) in 222 ms

得到dns的简短回答
$ dig +short cyberciti.biz
75.126.153.206

显示所有记录
$ dig +noall +answer cyberciti.biz any
cyberciti.biz. 3490 IN A 75.126.153.206
cyberciti.biz. 2733 IN NS NS2.NIXCRAFT.NET.
cyberciti.biz. 2733 IN NS NS1.NIXCRAFT.NET.
cyberciti.biz. 2733 IN NS NS4.NIXCRAFT.NET.
cyberciti.biz. 2733 IN NS NS5.NIXCRAFT.NET.
cyberciti.biz. 85668 IN RRSIG NSEC 8 2 86400 20101125013720 20101026010313 50568 biz. OjDv09mccTZR2bYCl4D57QcnNEkBq6bNEa20ExsI6NC2sI9pmiKLnq+w UnCYxWMnkMi7WNXwIhhUWtNhV48X3wJGj1Mufrhq8MnO25JIcRE6UJF2 y12TTZHHE0UJV6HSkw1sac3XlZKXLi/oSvE/IXTsdj2SckPh+pMlaieQ jAA=
cyberciti.biz. 85668 IN NSEC CYBERCITIZEN.biz. NS RRSIG NSEC

反向地址解析格式为
$ dig -x +short {IP-Address-here}

比如
$ dig -x 75.126.153.206 +short
www.cyberciti.biz.

找 SOA 记录
$ dig +nssearch cyberciti.biz
SOA ns1.nixcraft.net. vivek.nixcraft.com. 2008072353 10800 3600 604800 3600 from server ns5.nixcraft.net in 81 ms.
SOA ns1.nixcraft.net. vivek.nixcraft.com. 2008072353 10800 3600 604800 3600 from server ns4.nixcraft.net in 216 ms.
SOA ns1.nixcraft.net. vivek.nixcraft.com. 2008072353 10800 3600 604800 3600 from server ns1.nixcraft.net in 347 ms.
SOA ns1.nixcraft.net. vivek.nixcraft.com. 2008072353 10800 3600 604800 3600 from server ns2.nixcraft.net in 316 ms.

找 TTL 值格式为
$ dig +nocmd +noall +answer {TYPE} {example.com}

比如
$ dig +nocmd +noall +answer a cyberciti.biz
cyberciti.biz. 1642 IN A 75.126.153.206