# host

常用的分析域名查询工具

## 补充说明

**host命令** 是常用的分析域名查询工具，可以用来测试域名系统工作是否正常。

### 语法

```
host(选项)(参数)
```

### 选项

```
-a：显示详细的DNS信息；
-c<类型>：指定查询类型，默认值为“IN“；
-C：查询指定主机的完整的SOA记录；
-r：在查询域名时，不使用递归的查询方式；
-t<类型>：指定查询的域名信息类型；
-v：显示指令执行的详细信息；
-w：如果域名服务器没有给出应答信息，则总是等待，直到域名服务器给出应答；
-W<时间>：指定域名查询的最长时间，如果在指定时间内域名服务器没有给出应答信息，则退出指令；
-4：使用IPv4；
-6：使用IPv6.
```

### 参数

主机：指定要查询信息的主机信息。

### 实例

```
[root@localhost ~]# host www.jsdig.com 
www.jsdig.com is an alias for host.1.jsdig.com.
host.1.jsdig.com has address 100.42.212.8

[root@localhost ~]# host -a www.jsdig.com
Trying "www.jsdig.com"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34671
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.jsdig.com.               IN      ANY

;; ANSWER SECTION:
www.jsdig.com.        463     IN      CNAME   host.1.jsdig.com.

Received 54 bytes from 202.96.104.15#53 in 0 ms
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://hezhiqiang.gitbook.io/linux/ming-ling/host.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.