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DHCP协议详解及DHCP服务的配置

目录

• 一.DHCP概念
• 1.1、什么是DHCP
• 1.2、DHCP的作用
• 1.3、DHCP的好处
• 1.4、DHCP的架构
• 二.DHCP工作原理
• 三.DHCP种的租期
• 四.DHCP服务的配置
• 4.1、情况一
• 4.2、情况二
• 五.同网段时DHCP的配置
• 5.1、项目拓扑图
• 5.2、PC设置
• 5.3、二层交换机设置
• 5.4、三层交换机设置
• 5.5、ipconfig检测
• 六.DHCP中继配置（不同网段）
• 6.1、项目拓扑图
• 6.2、PC设置
• 6.3、二层交换机设置
• 6.4、三层交换机设置
• 6.5、路由器设置
• 6.6、ipconfig检测
• 七.总结

一.DHCP概念

1.1、什么是DHCP

DHCP——动态主机配置协议
DHCP：（动态主机配置协议）是一个局域网的网络协议。指的是由服务器控制一段IP地址范围，客户机登录服务器时就可以自动获得服务器分配的IP地址和子网掩码。默认情况下，DHCP作为Windows Server的一个服务组件不会被系统自动安装，还需要管理员手动安装并进行必要的配置。

1.2、DHCP的作用

为客户机分发IP地址，子网掩码，网关，DNS服务，租期等参数。

1.3、DHCP的好处

1.简化了客户机设置
2.防止用户误操作
3.避免了IP地址重复

1.4、DHCP的架构

架构为C/S结构：C——Client客户机 S——Server服务器
DHCP服务对应传输层是UDP协议，因为是C/S架构，所以DHCP服务是分为DHCP客户机占用UDP67号端口，DHCP服务器占用UDP68号端口

二.DHCP工作原理

（1）DHCP客户机发送DHCP discovery请求。注：DHCP客户机向DHCP服务器发送DHCP请求，来请求IP
（2）局域网中的所以DHCP服务器都会回复DHCP offer，为客户机提供IP地址
（3）客户机选择第一台DHCP服务器回复的IP地址，并且要发送DHCP request通告给局域网内所有的DHCP服务器，它选择了哪个IP和哪个DHCP服务器
备注：客户机发送DHCP request通告的原因有两层，第一层是通告给所有的DHCP服务器，让其他没有被选中的DHCP服务器把未使用到的地址进行回收，第二次是通告给被选中的DHCP服务器，这个地址DHCP的客户机要使用了。
被选中的DHCP服务器收到DHCP request消息后，会给DHCP客户机回复一个DHCP ack，正式确认此IP可以被客户机使用，DHCP客户机将此IP与自己的MAC绑定起来以便于下次继续使用，而其他DHCP服务器将把分配给DHCP客户机的IP回收。

三.DHCP种的租期

DHCP客户机使用IP地址是有限的。一般来说DHCP客户机使用DHCP分配得到的IP地址到了租期的50%时，会主动的向DHCP服务器发出续约请求，DHCP服务器接受到请求后，DHCP服务器会检查此IP地址有没有被别的DHCP客户机抢先占用，如果没有就续约成功，如果被占用则续约失败，此时DHCP客户机将重新发起DHCP discovery请求来获得新的IP地址

四.DHCP服务的配置

DHCP服务实现分为两种情况

4.1、情况一

DHCP服务器和DHCP客户机在同一网段

4.2、情况二

DHCP服务器和DHCP客户机不在同一网段，使用DHCP中继，只能由路由器来实现，DHCP服务器无法单独实现。

五.同网段时DHCP的配置

本次测试使用的eNSP软件

5.1、项目拓扑图

5.2、PC设置

所有PC机都按此设置，点击DHCP和自动获取DNS服务器地址

5.3、二层交换机设置

SW1：

<Huawei>
<Huawei>undo ter	
<Huawei>undo terminal mo	
<Huawei>undo terminal monitor 
Info: Current terminal monitor is off.
<Huawei>sys	
<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sys	
[Huawei]sysname SW1
[SW1]user-i	
[SW1]user-interface c	
[SW1]user-interface co	
[SW1]user-interface console 0
[SW1-ui-console0]idle-tim	
[SW1-ui-console0]idle-timeout 0 0
[SW1-ui-console0]q
[SW1]vlan bat 10 20
[SW1]int e0/0/1
[SW1-Ethernet0/0/1]port li	
[SW1-Ethernet0/0/1]port link-type access
[SW1-Ethernet0/0/1]port de	
[SW1-Ethernet0/0/1]port default vlan 10
[SW1-Ethernet0/0/1]int e0/0/2
[SW1-Ethernet0/0/2]port li	
[SW1-Ethernet0/0/2]port link-type access
[SW1-Ethernet0/0/2]port de	
[SW1-Ethernet0/0/2]port default vlan 20
[SW1-Ethernet0/0/2]q
[SW1]int g0/0/1
[SW1-GigabitEthernet0/0/1]port li	
[SW1-GigabitEthernet0/0/1]port link-type tr	
[SW1-GigabitEthernet0/0/1]port link-type trunk 
[SW1-GigabitEthernet0/0/1]port tr	
[SW1-GigabitEthernet0/0/1]port trunk all	
[SW1-GigabitEthernet0/0/1]port trunk allow-pass vlan all
[SW1-GigabitEthernet0/0/1]q

SW2：

<Huawei>undo terminal mo	
<Huawei>undo terminal monitor 
Info: Current terminal monitor is off.
<Huawei>sys	
<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sys	
[Huawei]sysname sw2
[sw2]user-in	
[sw2]user-interface co	
[sw2]user-interface console 0
[sw2-ui-console0]idle-ti	
[sw2-ui-console0]idle-timeout 0 0
[sw2-ui-console0]q
[sw2]vlan bat 10 20
Info: This operation may take a few seconds. Please wait for a moment...done.
[sw2]int e0/0/1
[sw2-Ethernet0/0/1]port l	
[sw2-Ethernet0/0/1]port link-type access
[sw2-Ethernet0/0/1]port de	
[sw2-Ethernet0/0/1]port default vlan 10
[sw2-Ethernet0/0/1]int e0/0/2
[sw2-Ethernet0/0/2]port li	
[sw2-Ethernet0/0/2]port link-type access
[sw2-Ethernet0/0/2]port de	
[sw2-Ethernet0/0/2]port default vlan 20
[sw2-Ethernet0/0/2]q
[sw2]int g0/0/1
[sw2-GigabitEthernet0/0/1]port li	
[sw2-GigabitEthernet0/0/1]port link-	
[sw2-GigabitEthernet0/0/1]port link-type tr	
[sw2-GigabitEthernet0/0/1]port link-type trunk 
[sw2-GigabitEthernet0/0/1]port po	
[sw2-GigabitEthernet0/0/1]port tr	
[sw2-GigabitEthernet0/0/1]port trunk all	
[sw2-GigabitEthernet0/0/1]port trunk allow-pass vlan all

5.4、三层交换机设置

LS1：

<Huawei>
<Huawei>undo ter	
<Huawei>undo terminal mo	
<Huawei>undo terminal monitor 
Info: Current terminal monitor is off.
<Huawei>sys	
<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sys	
[Huawei]sysname LS1
[LS1]user-in	
[LS1]user-interface co	
[LS1]user-interface console 0
[LS1-ui-console0]idle-tim	
[LS1-ui-console0]idle-timeout 0 0
[LS1-ui-console0]q
[LS1]vlan bat 10 20
Info: This operation may take a few seconds. Please wait for a moment...done.
[LS1]int g0/0/1
[LS1-GigabitEthernet0/0/1]port l	
[LS1-GigabitEthernet0/0/1]port link-t	
[LS1-GigabitEthernet0/0/1]port link-type tr	
[LS1-GigabitEthernet0/0/1]port link-type trunk 
[LS1-GigabitEthernet0/0/1]port tr	
[LS1-GigabitEthernet0/0/1]port trunk all	
[LS1-GigabitEthernet0/0/1]port trunk allow-pass vlan all
[LS1-GigabitEthernet0/0/1]int g0/0/2
[LS1-GigabitEthernet0/0/2]port l	
[LS1-GigabitEthernet0/0/2]port link-ty	
[LS1-GigabitEthernet0/0/2]port link-type tr	
[LS1-GigabitEthernet0/0/2]port link-type trunk 
[LS1-GigabitEthernet0/0/2]port tr	
[LS1-GigabitEthernet0/0/2]port trunk all	
[LS1-GigabitEthernet0/0/2]port trunk allow-pass vlan all
[LS1-GigabitEthernet0/0/2]q
[LS1]int vlan 10
[LS1-Vlanif10]q
[LS1]dhc	
[LS1]dhcp en	
[LS1]dhcp enable 
Info: The operation may take a few seconds. Please wait for a moment.done.
[LS1]int vlan 10
[LS1-Vlanif10]ip add 192.168.10.1 24
[LS1-Vlanif10]dhcp	
[LS1-Vlanif10]dhcp se	
[LS1-Vlanif10]dhcp select int 
[LS1-Vlanif10]dhcp se	
[LS1-Vlanif10]dhcp ser	
[LS1-Vlanif10]dhcp server dns	
[LS1-Vlanif10]dhcp server dns-list 4.4.4.4 8.8.8.8
[LS1-Vlanif10]q
[LS1]ip poo	
[LS1]ip pool dhcp 2^
Error:Too many parameters found at '^' position.
[LS1]ip pool dhcp2
Info:It's successful to create an IP address pool.
[LS1-ip-pool-dhcp2]net	
[LS1-ip-pool-dhcp2]network 192.168.20.0 ma	
[LS1-ip-pool-dhcp2]network 192.168.20.0 mask 24
[LS1-ip-pool-dhcp2]gate	
[LS1-ip-pool-dhcp2]gateway-l	
[LS1-ip-pool-dhcp2]gateway-list 192.168.20.1
[LS1-ip-pool-dhcp2]dns-li	
[LS1-ip-pool-dhcp2]dns-list 2.2.2.2 40.40.40.40
[LS1-ip-pool-dhcp2]lea	
[LS1-ip-pool-dhcp2]lease 	
[LS1-ip-pool-dhcp2]lease day 9
[LS1-ip-pool-dhcp2]q
[LS1]int vlan 20
[LS1-Vlanif20]ip add 192.168.20.1 24
[LS1-Vlanif20]dhc	
[LS1-Vlanif20]dhcp sr	
[LS1-Vlanif20]dhcp se	
[LS1-Vlanif20]dhcp select glo	
[LS1-Vlanif20]dhcp select global 

5.5、ipconfig检测

六.DHCP中继配置（不同网段）

6.1、项目拓扑图

6.2、PC设置

所有PC机都按此设置，点击DHCP和自动获取DNS服务器地址

6.3、二层交换机设置

SW1：

<Huawei>undo te	
<Huawei>undo terminal mo	
<Huawei>undo terminal monitor 
Info: Current terminal monitor is off.
<Huawei>sys	
<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sys	
[Huawei]sysname SW1
[SW1]user-in	
[SW1]user-interface co	
[SW1]user-interface console 0
[SW1-ui-console0]idle-t	
[SW1-ui-console0]idle-timeout 0 0
[SW1-ui-console0]q
[SW1]vlan bat 10 20
Info: This operation may take a few seconds. Please wait for a moment...done.
[SW1]int e0/0/1
[SW1-Ethernet0/0/1]port li	
[SW1-Ethernet0/0/1]port link-type acc	
[SW1-Ethernet0/0/1]port link-type access 
[SW1-Ethernet0/0/1]port de	
[SW1-Ethernet0/0/1]port default vlan 10
[SW1-Ethernet0/0/1]port l	
[SW1-Ethernet0/0/1]port link-type access
[SW1-Ethernet0/0/1]q
[SW1]int e0/0/2
[SW1-Ethernet0/0/2]port li	
[SW1-Ethernet0/0/2]port link-type access
[SW1-Ethernet0/0/2]port de	
[SW1-Ethernet0/0/2]port default vlan 20
[SW1-Ethernet0/0/2]q
[SW1]int g0/0/1
[SW1-GigabitEthernet0/0/1]port 	
[SW1-GigabitEthernet0/0/1]port l	
[SW1-GigabitEthernet0/0/1]port link-type t	
[SW1-GigabitEthernet0/0/1]port link-type trunk 
[SW1-GigabitEthernet0/0/1]port tr	
[SW1-GigabitEthernet0/0/1]port trunk al	
[SW1-GigabitEthernet0/0/1]port trunk allow-pass vlan all
[SW1-GigabitEthernet0/0/1]q

SW2：

<Huawei>undo shu	
<Huawei>undo ter	
<Huawei>undo terminal mo	
<Huawei>undo terminal monitor 
Info: Current terminal monitor is off.
<Huawei>sys	
<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sys	
[Huawei]sysname SW2
[SW2]user-imn	
[SW2]user-in	
[SW2]user-interface co	
[SW2]user-interface console 0
[SW2-ui-console0]idle-time	
[SW2-ui-console0]idle-timeout 0 0
[SW2-ui-console0]q
[SW2]vlan bat 10 20 
Info: This operation may take a few seconds. Please wait for a moment...done.
[SW2]int e0/0/1
[SW2-Ethernet0/0/1]port li	
[SW2-Ethernet0/0/1]port link-type a	
[SW2-Ethernet0/0/1]port link-type access 
[SW2-Ethernet0/0/1]port de	
[SW2-Ethernet0/0/1]port default vlan 10
[SW2-Ethernet0/0/1]int e0/0/2
[SW2-Ethernet0/0/2]port l	
[SW2-Ethernet0/0/2]port link-type a	
[SW2-Ethernet0/0/2]port link-type access 
[SW2-Ethernet0/0/2]port de	
[SW2-Ethernet0/0/2]port default vlan 20
[SW2-Ethernet0/0/2]q
[SW2]int g0/0/1
[SW2-GigabitEthernet0/0/1]port l	
[SW2-GigabitEthernet0/0/1]port link-type t	
[SW2-GigabitEthernet0/0/1]port link-type trunk 
[SW2-GigabitEthernet0/0/1]port tr	
[SW2-GigabitEthernet0/0/1]port trunk all	
[SW2-GigabitEthernet0/0/1]port trunk allow-pass vlan all
[SW2-GigabitEthernet0/0/1]q

6.4、三层交换机设置

LS1：

<Huawei>undo ter	
<Huawei>undo terminal mon	
<Huawei>undo terminal monitor 
Info: Current terminal monitor is off.
<Huawei>sys	
<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sys	
[Huawei]sysname LS1
[LS1]user-int	
[LS1]user-interface co	
[LS1]user-interface console 0
[LS1-ui-console0]idle-t	
[LS1-ui-console0]idle-timeout 0 0
[LS1-ui-console0]q
[LS1]vlan 100
[LS1-vlan100]q
[LS1]int g0/0/3
[LS1-GigabitEthernet0/0/3]port l	
[LS1-GigabitEthernet0/0/3]port link-ty	
[LS1-GigabitEthernet0/0/3]port link-type acc	
[LS1-GigabitEthernet0/0/3]port link-type access 
[LS1-GigabitEthernet0/0/3]port de	
[LS1-GigabitEthernet0/0/3]port default vlan 100
[LS1-GigabitEthernet0/0/3]q
[LS1]int vlan 100
[LS1-Vlanif100]ip add 10.10.10.1 24
[LS1-Vlanif100]q
[LS1]vlan bat 10 20
Info: This operation may take a few seconds. Please wait for a moment...done.
[LS1]dhcp e	
[LS1]dhcp enable 
Info: The operation may take a few seconds. Please wait for a moment.done.
[LS1]int vlan 10
[LS1-Vlanif10]dhcp se	
[LS1-Vlanif10]dhcp select re	
[LS1-Vlanif10]dhcp select relay 
[LS1-Vlanif10]dhcp re	
[LS1-Vlanif10]dhcp relay se	
[LS1-Vlanif10]dhcp relay server-ip 10.10.10.2
[LS1-Vlanif10]int vlan 20
[LS1-Vlanif20]dhcp se	
[LS1-Vlanif20]dhcp select re	
[LS1-Vlanif20]dhcp select relay 
[LS1-Vlanif20]dhcp re	
[LS1-Vlanif20]dhcp relay ser	
[LS1-Vlanif20]dhcp relay server-ip 10.10.10.2
[LS1]int vlan 10
[LS1-Vlanif10]ip add 192.168.10.1 24
[LS1-Vlanif10]int vlan 20
[LS1-Vlanif20]ip add 192.168.20.1 24

6.5、路由器设置

R1:

<Huawei>undo ter	
<Huawei>undo terminal mo	
<Huawei>undo terminal monitor 
Info: Current terminal monitor is off.
<Huawei>sys	
<Huawei>system-view 
Enter system view, return user view with Ctrl+Z.
[Huawei]sys	
[Huawei]sysname R1
[R1]user-int	
[R1]user-interface co	
[R1]user-interface console 0
[R1-ui-console0]idle-t	
[R1-ui-console0]idle-timeout 0 0
[R1-ui-console0]q
[R1]int g0/0/0
[R1-GigabitEthernet0/0/0]ip add 10.10.10.2 24
[R1-GigabitEthernet0/0/0]undo shu	
[R1-GigabitEthernet0/0/0]undo shutdown 
Info: Interface GigabitEthernet0/0/0 is not shutdown.
[R1-GigabitEthernet0/0/0]q
[R1]dhcp e	
[R1]dhcp enable 
Info: The operation may take a few seconds. Please wait for a moment.done.
[R1]int g0/0/0
[R1-GigabitEthernet0/0/0]dhcp se	
[R1-GigabitEthernet0/0/0]dhcp select gl	
[R1-GigabitEthernet0/0/0]dhcp select global 
[R1-GigabitEthernet0/0/0]q
[R1]ip rou	
[R1]ip route-st	
[R1]ip route-static 192.168.10.0 24 10.10.10.1
[R1]ip route-static 192.168.20.0 24 10.10.10.1
[R1]ip pool de	
[R1]ip pool dh	
[R1]ip pool dhcp1
Info:It's successful to create an IP address pool.
[R1-ip-pool-dhcp1]net	
[R1-ip-pool-dhcp1]network 192.168.10.0 ma	
[R1-ip-pool-dhcp1]network 192.168.10.0 mask 24
[R1-ip-pool-dhcp1]ga	
[R1-ip-pool-dhcp1]gateway-list 192.168.10.1
[R1-ip-pool-dhcp1]dns	
[R1-ip-pool-dhcp1]dns-list 6.6.6.6 8.8.8.8
[R1-ip-pool-dhcp1]lea	
[R1-ip-pool-dhcp1]lease da	
[R1-ip-pool-dhcp1]lease day 9
[R1-ip-pool-dhcp1]q
[R1]ip pool dhcp2
Info:It's successful to create an IP address pool.
[R1-ip-pool-dhcp2]ne	
[R1-ip-pool-dhcp2]net	
[R1-ip-pool-dhcp2]network 192.168.20.0 ma	
[R1-ip-pool-dhcp2]network 192.168.20.0 mask 24
[R1-ip-pool-dhcp2]gat	
[R1-ip-pool-dhcp2]gateway-list 192.168.20.1
[R1-ip-pool-dhcp2]dns	
[R1-ip-pool-dhcp2]dns-list 20.20.20.20 9.9.9.9
[R1-ip-pool-dhcp2]lea	
[R1-ip-pool-dhcp2]lease day 9

6.6、ipconfig检测

七.总结

本文标签： DHCP协议详解及DHCP服务的配置