DHCP简介

什么是DHCP：

           DHCP动态主机配置协议，是一个应用层协议。当我们将客户主机IP地址设置为动态获取方式时，DHCP服务器就会根据DHCP协议给客户端分配ip，

使得客户机能利用ip上网。

DHCP工作原理：

           

第一步：客户端通过广播发送DHCP Discover 报文寻找服务器端

第二步：服务器端通过单播发送DHCP Offer 报文向客户端提供IP地址等网络信息

第三步：客户端通过广播发送DHCP Request 报文告知服务器端本地选择使用哪个IP地址

第四步：服务器通过单播发送DHCP Ack报文告知客户端IP地址是合法可用的

下面通过一个ensp实验诠释DHCP服务↓↓↓

LSW1

<Huawei>

<Huawei>un te m

<Huawei>sys

[Huawei]sys LSW1

[LSW1]vlan b

[LSW1]vlan batch 10 20

[LSW1]int e0/0/1

[LSW1-Ethernet0/0/1]port link-type access

[LSW1-Ethernet0/0/1]port default vlan 10

[LSW1-Ethernet0/0/1]un sh

Info: Interface Ethernet0/0/1 is not shutdown.

[LSW1-Ethernet0/0/1]int e0/0/2

[LSW1-Ethernet0/0/2]p l a

[LSW1-Ethernet0/0/2]p d v 20

[LSW1-Ethernet0/0/2]un sh

[LSW1-Ethernet0/0/2]int e0/0/3

[LSW1-Ethernet0/0/3]p l a

[LSW1-Ethernet0/0/3]p d v 10

[LSW1-Ethernet0/0/3]un sh

[LSW1-Ethernet0/0/3]int e0/0/4

[LSW1-Ethernet0/0/4]p l a

[LSW1-Ethernet0/0/4]p d v 20

[LSW1-Ethernet0/0/4]un sh

[LSW1-Ethernet0/0/4]int g0/0/1

[LSW1-GigabitEthernet0/0/1]p l t

[LSW1-GigabitEthernet0/0/1]p t a v a

[LSW1-GigabitEthernet0/0/1]un sh

R1

<Huawei>un te m

<Huawei>sys

[Huawei]sys R1

[R1]dhcp enable   ##开启DHCP功能

[R1]int g0/0/1.10  ##进入子接口

[R1-GigabitEthernet0/0/1.10]dot1q termination vid 10

[R1-GigabitEthernet0/0/1.10]ip add 192.168.10.1 24

[R1-GigabitEthernet0/0/1.10]arp broadcast enable

[R1-GigabitEthernet0/0/1.10]dhcp select interface  ##基于接口配置DHCP

[R1-GigabitEthernet0/0/1.10]dhcp server dns-list 2.2.2.2 8.8.8.8  ##配置dns

[R1-GigabitEthernet0/0/1.10]q

[R1]int g0/0/1.20

[R1-GigabitEthernet0/0/1.20]d t v 20                                                

[R1-GigabitEthernet0/0/1.20]ip add 192.168.20.1 24

[R1-GigabitEthernet0/0/1.20]a b e

[R1-GigabitEthernet0/0/1.20]dhcp select interface

[R1-GigabitEthernet0/0/1.20]dhcp server dns-list 2.2.2.2 8.8.8.8

[R1-GigabitEthernet0/0/1.20]q

[R1]int g0/0/0

[R1-GigabitEthernet0/0/0]ip add 12.0.0.1 24

[R1-GigabitEthernet0/0/0]un sh

[R1-GigabitEthernet0/0/0]q

[R1]ip route-static 0.0.0.0 0.0.0.0 12.0.0.2  ##设置静态路由

R2

<Huawei>un te m

<Huawei>sys

[Huawei]sys R2

[R2]dhcp en

[R2]dhcp enable

Info: The operation may take a few seconds. Please wait for a moment.done.

[R2]int g0/0/0

[R2-GigabitEthernet0/0/0]ip add 12.0.0.2 24

[R2-GigabitEthernet0/0/0]un sh

[R2-GigabitEthernet0/0/0]int g0/0/1

[R2-GigabitEthernet0/0/1]ip add 15.0.0.1 24

[R2-GigabitEthernet0/0/1]dhcp select global

[R2-GigabitEthernet0/0/1]un sh

[R2-GigabitEthernet0/0/1]q

[R2]ip pool dhcp15

Info:It's successful to create an IP address pool.

[R2-ip-pool-dhcp15]network 15.0.0.0 mask 24

[R2-ip-pool-dhcp15]gateway-list 15.0.0.1

[R2-ip-pool-dhcp15]dns-list 8.8.8.8 2.2.2.2

[R2-ip-pool-dhcp15]q

[R2]ip route-static 0.0.0.0 0.0.0.0 12.0.0.1

配置完后抓包检测是否开通