在三层交换机配置DHCP的方法分享（3层交换机dhcp划分）

来源：最后更新：2024-04-09 00:10:22

导读：在三层交换机配置DHCP的方法分享通过本实验掌握，如何在Cisco Catalyst 3550交换机来配置DHCP服务，实现对内网主机分配IP地址，网关，DN

The Beginning

通过本实验掌握，如何在Cisco Catalyst 3550交换机来配置DHCP服务，实现对内网主机分配IP地址，网关，DNS，WINS，租期，域名等。可能你之前是在windows Server服务器或者Cisco Router 部署过DHCP,但在工程项目中，根据需求，大多是在接入层或者汇聚层多层交换机来配置的，可以同时实现DHCP Snooping等技术。Wth育儿早教网

在三层交换机配置DHCP的方法分享 Wth育儿早教网

实验过程：Wth育儿早教网

第一步：Catalyst 3550底层配置Wth育儿早教网
Switch(config)#no ip do loWth育儿早教网
Switch(config)#line con 0Wth育儿早教网
Switch(config-line)#no exec-tWth育儿早教网
Switch(config-line)#logg synWth育儿早教网
Switch(config-line)#host Switch_DhcpWth育儿早教网
Switch_Dhcp(config)#int f0/1Wth育儿早教网
Switch_Dhcp(config-if)#no shWth育儿早教网
Switch_Dhcp(config-if)#spanning-tree portfastWth育儿早教网
//连接终端的接口下，开启portfast特性，跳过生成树的选举，接口立即进入转发状态Wth育儿早教网
%Warning: portfast should only be enabled on ports connected to a singleWth育儿早教网
host. Connecting hubs, concentrators, switches, bridges, etc... to thisWth育儿早教网
interface when portfast is enabled, can cause temporary bridging loops.Wth育儿早教网
Use with CAUTIONWth育儿早教网
%Portfast has been configured on FastEthernet0/1 but will onlyWth育儿早教网
have effect when the interface is in a non-trunking mode.Wth育儿早教网
Switch_Dhcp(config-if)#endWth育儿早教网
第二步: 开启DHCP服务，定义分配地址池范围及掩码，网关，DNS，域名，租期等Wth育儿早教网
//全局下开启DHCP服务，该服务默认是关闭的Wth育儿早教网
Switch_Dhcp(config)#service dhcpWth育儿早教网
//关闭DHCP分配冲突，日志记录消息Wth育儿早教网
Switch_Dhcp(config)#no ip dhcp conflict loggingWth育儿早教网
//创建DHCP地址池，名称为可以是任意字符Wth育儿早教网
Switch_Dhcp(config)#ip dhcp pool ciscoWth育儿早教网
//指定要通过DHCP分配的网段和掩码，还有另外一种写法（192.168.0.0 255.255.255.0）Wth育儿早教网
Switch_Dhcp(dhcp-config)#network 192.168.0.0 /24Wth育儿早教网
//指定分配的网关地址Wth育儿早教网
Switch_Dhcp(dhcp-config)#default-router 192.168.0.1Wth育儿早教网
//指定DHCP域名，域名可以为任意字符Wth育儿早教网
Switch_Dhcp(dhcp-config)#domain-name www.cisco.com.cnWth育儿早教网
//指定PC通过DHCP分配到DNS地址，（这里指定的是当地电信部门的真实地址，全国各地市不一样的）Wth育儿早教网
Switch_Dhcp(dhcp-config)#dns 218.30.19.40 61.134.1.4Wth育儿早教网
//netbios服务器地址，可选的配置Wth育儿早教网
Switch_Dhcp(dhcp-config)#netbios-name-server 192.168.0.10Wth育儿早教网
//指定通过DHCP分配到地址，租期为永久Wth育儿早教网
Switch_Dhcp(dhcp-config)#lease infiniteWth育儿早教网
Switch_Dhcp(dhcp-config)#endWth育儿早教网
//指定不通过DHCP 地址池中分配的地址，也就是排除的地址。如果这些地址被分配给PC使用，就有可能造成网络中IP地址冲突。如：192.168.0.1 是网关地址，该地址只能是分配所有PC做网关地址，不能做IP地址使用。所以要排除。Wth育儿早教网
Switch_Dhcp(config)#ip dhcp excluded-address 192.168.0.1Wth育儿早教网
Switch_Dhcp(config)# ip dhcp excluded-address 192.168.0.10Wth育儿早教网
第三步：查看VLAN信息，并启用SVI接口Wth育儿早教网

复制代码Wth育儿早教网
Wth育儿早教网
代码如下:Wth育儿早教网

Switch_Dhcp#show vlan briefWth育儿早教网
VLAN Name Status PortsWth育儿早教网
---- -------------------------------- --------- -------------------------------Wth育儿早教网
1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4Wth育儿早教网
Fa0/5, Fa0/6, Fa0/7, Fa0/8Wth育儿早教网
Fa0/9, Fa0/10, Fa0/11, Fa0/12Wth育儿早教网
Fa0/13, Fa0/15, Fa0/16, Fa0/17Wth育儿早教网
Fa0/18, Fa0/19, Fa0/20, Fa0/21Wth育儿早教网
Fa0/22, Fa0/23, Fa0/24, Gi0/1Wth育儿早教网
Gi0/2Wth育儿早教网
1002 fddi-default act/unsupWth育儿早教网
1003 token-ring-default act/unsupWth育儿早教网
1004 fddinet-default act/unsupWth育儿早教网
1005 trnet-default act/unsupWth育儿早教网
Switch_Dhcp#conf tWth育儿早教网
Enter configuration commands, one per line. End with CNTL/Z.Wth育儿早教网
//进入管理VLAN1 下，启用SVI功能Wth育儿早教网
Switch_Dhcp(config)#int vlan 1Wth育儿早教网
//配置VLAN的地址为192.168.0.1 掩码为24位，默认情况下Cisco Catalyst交换机所有的物理接口都属于VLAN1，此地址也就是PC网关地址。Wth育儿早教网
Switch_Dhcp(config-if)#ip add 192.168.0.1 255.255.255.0Wth育儿早教网
Switch_Dhcp(config-if)#no shWth育儿早教网
Switch_Dhcp(config-if)#endWth育儿早教网
Switch_Dhcp#Wth育儿早教网
00:09:07: %SYS-5-CONFIG_I: Configured from console by consoleWth育儿早教网
Switch_Dhcp#Wth育儿早教网
00:09:08: %LINK-3-UPDOWN: Interface Vlan1, changed state to upWth育儿早教网
00:09:09: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state toWth育儿早教网

第四步：查看当前交换机配置文件Wth育儿早教网

复制代码Wth育儿早教网
Wth育儿早教网
代码如下:Wth育儿早教网

//验证DHCP的配置信息Wth育儿早教网
Switch_Dhcp#sh run | begin ip dhcpWth育儿早教网
no ip dhcp conflict loggingWth育儿早教网
ip dhcp excluded-address 192.168.0.1Wth育儿早教网
ip dhcp excluded-address 192.168.0.10Wth育儿早教网
!Wth育儿早教网
ip dhcp pool ciscoWth育儿早教网
network 192.168.0.0 255.255.255.0Wth育儿早教网
default-router 192.168.0.1Wth育儿早教网
domain-name www.cisco.com.cnWth育儿早教网
dns-server 218.30.19.40 61.134.1.4Wth育儿早教网
netbios-name-server 192.168.0.10Wth育儿早教网
lease infiniteWth育儿早教网
interface Vlan1Wth育儿早教网
ip address 192.168.0.1 255.255.255.0Wth育儿早教网

第五步：此时将PC1的网线插入Catalyst 3550 的F0/1接口，并在PC上查看IP地址获得信息。PC上的本地连接，TCP/IP 设置为自动获得IP地址形式。Wth育儿早教网
PC上查看方法：开始-运行-cmd-ipconfig/allWth育儿早教网

在三层交换机配置DHCP的方法分享 Wth育儿早教网

从以上信息可以得出，PC已经能从DHCP服务器获得IP地址等信息，实验现象成功。Wth育儿早教网

第六步：查看交换机DHCP 动态绑定，以及交换机DHCP Server状态信息Wth育儿早教网

复制代码Wth育儿早教网
Wth育儿早教网
代码如下:Wth育儿早教网

//查看DHCP动态绑定信息，从这里可以看到PC，从DHCP地址池中的得到IP地址，以及PC的MAC地址等Wth育儿早教网
Switch_Dhcp#show ip dhcp bindingWth育儿早教网
IP address Client-ID/ Lease expiration TypeWth育儿早教网
Hardware addressWth育儿早教网
192.168.0.2 0100.16d3.249f.fd Infinite AutomaticWth育儿早教网
//查看DHCP服务器工作状态Wth育儿早教网
Switch_Dhcp#show ip dhcp server statisticsWth育儿早教网
Memory usage 5661Wth育儿早教网
Address pools 1Wth育儿早教网
Database agents 0Wth育儿早教网
Automatic bindings 1Wth育儿早教网
Manual bindings 0Wth育儿早教网
Expired bindings 0Wth育儿早教网
Malformed messages 0Wth育儿早教网
Message ReceivedWth育儿早教网
BOOTREQUEST 0Wth育儿早教网
DHCPDISCOVER 2Wth育儿早教网
DHCPREQUEST 3Wth育儿早教网
DHCPDECLINE 0Wth育儿早教网
DHCPRELEASE 0Wth育儿早教网
DHCPINFORM 3Wth育儿早教网
Message SentWth育儿早教网
BOOTREPLY 0Wth育儿早教网
DHCPOFFER 2Wth育儿早教网
DHCPACK 6Wth育儿早教网
DHCPNAK 0Wth育儿早教网
Switch_Dhcp#Wth育儿早教网
Switch_Dhcp#clear ip dhcp binding *Wth育儿早教网

第七步：使用debug 调试命令查看PC申请IP地址过程（DHCP工作过程）Wth育儿早教网
在PC上：开始-运行-cmd-ipconfig /release (释放获得IP地址)Wth育儿早教网
重新申请IP地址ipconfig /renewWth育儿早教网
此时查看交换机日志信息Wth育儿早教网

复制代码Wth育儿早教网
Wth育儿早教网
代码如下:Wth育儿早教网

Switch_Dhcp#debug ip dhcp server eventsWth育儿早教网
01:13:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to upWth育儿早教网
Switch_Dhcp#Wth育儿早教网
01:13:13: DHCPD: DHCPDISCOVER received from client 0100.16d3.249f.fd on interface Vlan1.Wth育儿早教网
Switch_Dhcp#Wth育儿早教网
01:13:20: DHCPD: assigned IP address 192.168.0.3 to client 0100.16d3.249f.fd.Wth育儿早教网
01:13:20: DHCPD: Sending DHCPOFFER to client 0100.16d3.249f.fd (192.168.0.3).Wth育儿早教网
01:13:20: DHCPD: broadcasting BOOTREPLY to client 0016.d324.9ffd.Wth育儿早教网
01:13:20: DHCPD: DHCPREQUEST received from client 0100.16d3.249f.fd.Wth育儿早教网
01:13:20: DHCPD: Sending DHCPACK to client 0100.16d3.249f.fd (192.168.0.3).Wth育儿早教网
01:13:20: DHCPD: broadcasting BOOTREPLY to client 0016.d324.9ffd.Wth育儿早教网
Switch_Dhcp#Wth育儿早教网
01:13:23: DHCPD: DHCPINFORM received from client 0100.16d3.249f.fd (192.168.0.3).Wth育儿早教网
01:13:23: DHCPD: Sending DHCPACK to client 0100.16d3.249f.fd (192.168.0.3).Wth育儿早教网
01:13:23: DHCPD: unicasting BOOTREPLY to client 0016.d324.9ffd (192.168.0.3).Wth育儿早教网