每天一条Linux命令(23) host (域名查询工具)

在Linux系统中，命令 host 用于查询DNS的工具，他可以将指定主机名称转换为IP地址。

什么又是NDS?

DNS(Domain Name System)翻译为域名解析系统，作用是将域名解析为机器看得懂的Ip地址，这个过程叫做域名解析。（后续会详细讲述什么是DNS）

语法：

host [参数选项]

参数说明：

-a显示详细的DNS信息

-t指定查询的域名信息类型，可以是 “A”、“ALL”、“MX” 和“NS”等

案例：

NDS查询

[root@master test03]# host-bash:host:commandnotfound

好吧，找不到命令。使用下列命令进行安装

CnetOS环境：

yum install bind-utils

Ubuntu环境：

sudo apt-get install bind-utils

本案例环境为CentOS,开始安装

[root@master test03]# yum install bind-utilsLoaded plugins: fastestmirrorLoading mirror speeds from cached hostfileCould not retrieve mirrorlist /?release=7&arch=x86_64&repo=os&infra=stock error was14: curl#6 - "Could not resolve host: ; Unknown error"* base:* extras:* updates:base| 3.6 kB 00:00:00http://mirrors./centos/7.8./extras/x86_64/repodata/repomd.xml: [Errno 14] curl#6 - "Could not resolve host: mirrors.; Unknown error"Total download size: 3.1 MInstalled size: 7.5 MIsthisok[y/d/N]:y#这里输入y表示同意安装Downloading packages:......#略geoipupdate.x86_64 0:2.5.0-1.el7Complete![root@mastertest03]#

再次查询

[root@master test03]# hosthas address 47.92.108.93has IPv6 address 2408:4001:f10::1a6is an alias for ..[root@mastertest03]#

-a 查询详细信息

[root@master test03]# host -aTrying "";; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48133;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0;; QUESTION SECTION:;. IN ANY;; ANSWER SECTION:. 567 IN CNAME ..Received 73 bytes from 8.8.8.8#53 in 32 ms[root@mastertest03]#

指定DNS服务器查询

[root@master test03]# host -a 223.5.5.5Trying ""Using domain server:Name: 223.5.5.5Address: 223.5.5.5#53Aliases:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7025;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0;; QUESTION SECTION:;. IN ANY;; ANSWER SECTION:. 115 IN A 47.92.108.93. 115 IN AAAA 2408:4001:f10::1a6Received 77 bytes from 223.5.5.5#53 in 11 ms[root@mastertest03]#

-t 按类进行查询

[root@master test03]# host -t MXis an alias for ..[root@mastertest03]#