Experiment content : GNS3 in analog implementation of DHCP relay service
Experimental environment: server a Linux system as a DHCP server, dhcp package is installed, the card is only the host mode, the binding vmnet1
Two win10 client system, the card is only the host mode. Respectively binding vmnet2 and vmnet8
GNS3 virtual network software
experiment procedure:
(A), open Linux configuration. In the first vmnet8 nat network mode will DHCPF service is installed on a Linux system, then switch to custom mode bindings vmnet1. Configure a static IP, DHCP server configuration.
1, with the yum package repository to download and install DHCP
[Root @ localhost ~] # yum install dhcp -y install DHCP package
2, custom mode is switched to the binding vmnet1
3, configure a static IP, and restart network services
[Root @ localhost ~] # vim / etc / sysconfig / network-scripts / ifcfg-ens33 change the configuration of static IP
4, the dhcp server, the file is empty at this time of DHCP service, you need to copy and use templates to find the DHCP configuration file, and then configure the DHCP service on the configuration is complete.
[Root @ localhost ~] # rpm -qc dhcp dhcp see the main configuration file path
[Root @ localhost ~] # cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf the dhcp main configuration file templates to cover their own dhcp file directory
[Root @ localhost ~] # vim /etc/dhcp/dhcpd.conf the dhcp service
[root@localhost ~]# systemctl start dhcpd 启动dhcpd服务
（二）、将win10-1和win10-2切换为自定义并分别绑定vmnet2和vmnet8
1、wein10-1绑定vmnet2
2、关闭vmnet8的联网功能，及dhcp功能
3、将win10-2改为自定义模式，绑定vmnet8
(三)、在GNS3中搭建服务架构，对其中的设备进行配置
1、打开GNS3配置拓扑图，布置两台win10主机，一台dhcp服务器（Linux），一台二层交换机，一台三层交换机
2，将设备相互连接如下:
win1的vmnet2连接到sw2的f1/2
win2的vmnet8连接到sw2的f1/3
dhcp的vmnet1连接到sw2的f1/1
sw2的f1/0连接到sw3的f1/0
设置完成并全部开启，并显示端口号
3，双击打开sw2对二层交换进行vlan划分
win10-1：vlan10 192.168.10.1/24
win10-2：vlan20 192.168.20.1/24
dhcp：vlan100 192.168.100.1/24
双击打开sw2进行配置vlan
f1/1:vlan100
f1/2:vlan10
f1/3:vlan20
sw2#configure terminal 进入全局模式
sw2(config)#vlan 10,20,100 创建三个vlan
sw2(config-vlan)#ex 退出vlan
sw2(config)#do show vlan-switch brief 查看创建的vlan的信息
sw2(config)#interface f1/1 进入f1/1的接口模式
sw2(config-if)#switch mod access 设置access模式
sw2(config-if)#switch access vlan 100 将端口分配给vlan100中
sw2(config-if)#ex sw2(config)#interface f1/2 设置f1/2的接口模式
sw2(config-if)#switch mod access
sw2(config-if)#switch access vlan 10
sw2(config-if)#ex sw2(config)#interface f1/3 设置f1/3的接口模式
sw2(config-if)#switch mod access
sw2(config-if)#switch access vlan 20
sw2(config-if)#ex sw2(config)#do show vlan-sw b 查看vlan的划分信息
sw2(config)#interface f1/0 进入f1/0接口
sw2(config-if)#switch mod trunk 设置中继链路模式
sw2(config-if)#switch trunk encapsulation dot1q 选择封装类型为dot1q
sw2(config-if)#ex
sw2(config)#no ip routing 关闭路由功能
sw2(config)#do show int f1/0 switchport 查看接口f1/0的接口信息
4、双击打开sw3三层交换进行配置
创建三个vlan10，20，100
将f1/0接口设置为trunk链路
设置vlan10的网关子网掩码192.168.10.1 255.255.255.0
设置vlan20的网关子网掩码192.168.20.1 255.255.255.0
设置vlan100的网关子网掩码 192.168.100.1 255.255.255.0
sw3#configure terminal 进入全局模式
sw3(config)#vlan 10,20,100 创建三个vlan
sw3(config-vlan)#ex 退出vlan
sw3(config)#do show vlan-switch brief 查看创建的vlan的信息
sw3(config)#interface f1/0 进入f1/0接口
sw3(config-if)#switch mod trunk 设置中继链路模式
sw3(config-if)#switch trunk encapsulation dot1q 选择封装类型为dot1q
sw3(config-if)#ex
sw3(config)#do show int f1/0 switchport 查看接口f1/0的接口信息
w3(config)#int vlan 10 进入vlan10
sw3(config-if)#ip add 192.168.10.1 255.255.255.0 设置vlan10的网关及子网掩码
sw3(config-if)#no shut 开启vlan10
sw3(config-if)#ex
sw3(config)#int vlan 20 设置vlan20
sw3(config-if)#ip add 192.168.20.1 255.255.255.0
sw3(config-if)#no shut
sw3(config-if)#ex
sw3(config)#int vlan 100 设置vlan100
sw3(config-if)#ip add 192.168.100.1 255.255.255.0
sw3(config-if)#no shut
sw3(config-if)#end 退出全局模式
sw3#show ip interface brief 查看vlan设置情况
（四）在网关中配置DHCP中继
w3#conf t 进入全局模式
sw3(config)#int vlan 10 设置网关中的DHCP中继
sw3(config-if)#ip helper-address 192.168.100.100
sw3(config-if)#no shut
sw3(config-if)#ex
sw3(config)#int vlan 20
sw3(config-if)#ip helper-address 192.168.100.100
sw3(config-if)#no shut
sw3(config-if)#ex
sw3(config)#int vlan 100
sw3(config-if)#ip helper-address 192.168.100.100
sw3(config-if)#no shut
(E), open to see if the two hosts can obtain an IP address automatically segment 10/20
1, open win10-1 enter cmd Type ipconfig, see the IP address
2, open win10-2 enter cmd Type ipconfig, see the IP address
DHCP relay service set up the experiment.