关于DHCP的简单理解

短命女 2023-06-07 05:43 10阅读 0赞

###### 1、DHCP这个在网络中的高频词是什么？（what） ######

DHCP:动态主机配置协议（Dynamic Host Configuration Protocol）,从名称中我们可以看出，这是一个**协议**，并且该协议的工作任务是**主机配置** ，方式是**动态**的！，这就是我们一开始的印象 ！

接下来，我们在进一步探究：  
**动态**，**主机** ，**配置**，**协议**

**Dynamic** – Automatically  
**Host** – Any computer that is connected to the network  
**Configuration** – To configure a host means to provide network information(ip address,subnet mask,Gateway address) to a host  
**Protocol** – Set of rules

###### 2、DHCP 是 怎么工作的？（how） ######

在探究DHCP是怎么工作之前，我们需要看一看DHCP是由什么的?

Components of DHCP:  
**DHCP server**: A networked device running the DCHP service that holds IP addresses and related configuration information. This is most typically a server or a router but could be anything that acts as a host, such as an SD-WAN appliance.  
**DHCP client**: The endpoint that receives configuration information from a DHCP server. This can be a computer, mobile device, IoT endpoint or anything else that requires connectivity to the network. Most are configured to receive DHCP information by default.  
**IP address pool**: The range of addresses that are available to DHCP clients. Addresses are typically handed out sequentially from lowest to highest.  
**Subnet**: IP networks can be partitioned(分割) into segments(部分、段) known as subnets. Subnets help keep networks manageable.  
**Lease**: The length of time for which a DHCP client holds the IP address information. When a lease(租期) expires(到期), the client must renew it.  
**DHCP relay**: A router or host that listens for client messages being broadcast on that network and then forwards them to a configured server. The server then sends responses back to the relay agent(中继代理) that passes them along to the client. This can be used to centralize(中心化) DHCP servers instead of having a server on each subnet.

了解到dhcp的组成之后我们以图示的方式展示dhcp的工作过程：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpZ2h0X1RyYXZsbGluZw_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpZ2h0X1RyYXZsbGluZw_size_16_color_FFFFFF_t_70 1]  
dhcp服务器设置  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpZ2h0X1RyYXZsbGluZw_size_16_color_FFFFFF_t_70 2]  
下图中除了客户端的请求与服务器端的响应之外，还展示了dhcp的状态转换：initializing(初始化)、selecting(选择)、requesting(请求)、bound(绑定)、\[renewing(续租)、rebinding(重新绑定)\]，具体细节自己查询资料。![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpZ2h0X1RyYXZsbGluZw_size_16_color_FFFFFF_t_70 3]

###### 3、我们作为是怎么成为dhcp client？在哪配置的？（where） ######

关于dhcp的配置如下图:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpZ2h0X1RyYXZsbGluZw_size_16_color_FFFFFF_t_70 4]  
上面是我电脑上的关于以太网的network information，我们也可以 观察到，默认网关和DHCP服务器是同一个ip地址![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpZ2h0X1RyYXZsbGluZw_size_16_color_FFFFFF_t_70 5][]

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