在一台三层交换上，通过配置dhcp和路由实现不同VLAN相互通信

本实验需求：
通过在cisco catalyst 3550来规划VLAN 100 和VLAN 200，并且配置DHCP 让VLAN100人事部计算机获得IP地址为192.168.0.0/24，让VLAN200市场部计算机获得IP地址为172.16.0.0/24。因为市场部和人事部因为业务上的关系，需要两台服务器相互通信，所在还需要在3550上配置VLAN间相互通信。

实验拓扑：


实验过程 第一步 配置Catalyst 3550基础配置

Switch> Switch>enable Switch#conf t Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#host 3550 3550(config)#no ip do lo 3550(config)#line con 0 3550(config-line)#no exec-t 3550(config-line)#logg syn 3550(config-line)#exit

第二步 在Catalyst 3550 划分VLAN 100和VLAN 200

//进入全局配置模式下，划分VLAN(请问catalyst 3500支持在全局模式下划分VLAN吗？) 3550(config)#vlan 100 //给VLAN100命名 3550(config-vlan)#name renshibo 3550(config-vlan)#int f0/13 3550(config-if)#switchport mode access 3550(config-if)#switchport access vlan 100 3550(config-if)#spanning-tree portfast //请问什么时候需要在交换机接口下配置portfast？这里如果不配置可以吗？ %Warning: portfast should only be enabled on ports connected to a single host. Connecting hubs, concentrators, switches, bridges, etc... to this interface when portfast is enabled, can cause temporary bridging loops. Use with CAUTION %Portfast has been configured on FastEthernet0/13 but will only have effect when the interface is in a non-trunking mode. 3550(config-if)#vlan 200 3550(config-vlan)#name shichangbo 3550(config-vlan)#int f0/15 3550(config-if)#sw mo acc 3550(config-if)#sw acc vlan 200 3550(config-if)#spanning-tree portfast %Warning: portfast should only be enabled on ports connected to a single host. Connecting hubs, concentrators, switches, bridges, etc... to this interface when portfast is enabled, can cause temporary bridging loops. Use with CAUTION %Portfast has been configured on FastEthernet0/15 but will only have effect when the interface is in a non-trunking mode. //验证VLAN的配置 3550#show vlan brief VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4 Fa0/5, Fa0/6, Fa0/7, Fa0/8 Fa0/9, Fa0/10, Fa0/11, Fa0/12 Fa0/14, Fa0/16, Fa0/17, Fa0/18 Fa0/23, Gi0/1, Gi0/2 100 renshibo active Fa0/13 200 shichangbo active Fa0/15 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup

第三步 配置SVI(交换虚拟接口)

3550#conf t Enter configuration commands, one per line. End with CNTL/Z. //进入VLAN 100 虚拟接口下 3550(config)#int vlan 100 //增加接口描述，以便将来排错更加方便 3550(config-if)#description Connection to renshibo //这里配置的IP地址就是人事部PC的默认网关地址，如果VLAN接口不配置IP地址，后面的DHCP配置中，PC能否获得IP地址吗？？ 3550(config-if)#ip add 192.168.0.1 255.255.255.0 3550(config-if)#no sh 3550(config-if)#int vlan 200 00:13:22: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan200, changed state to up 3550(config-if)#description Connection to shichangbo 3550(config-if)#ip add 172.16.0.1 255.255.255.0 3550(config-if)#no sh 3550(config-if)# 3550#conf t //开启catalyst 3550三层交换路由功能（默认是关闭的） 请问cisco catalyst那些型号交换机是三层交换机？ 3550(config)#ip routing 3550(config)#exit 3550#sh ip route //两条直连路由条目 Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route Gateway of last resort is not set 172.16.0.0/24 is subnetted, 1 subnets C 172.16.0.0 is directly connected, Vlan200 C 192.168.0.0/24 is directly connected, Vlan100 Designated bridge has priority 32768, address ccd1.0a80.0000 Designated port id is 129.65, designated path cost 0 Timers: message age 0, forward delay 0, hold 0 Number of transitions to forwarding state: 1 BPDU: sent 993, received 92

第四步 在Catalyst 3550上配置DHCP，以便于VLAN100和VLAN200下客户端获得IP地址，掩码，网关，DNS等

//全局下打开DHCP服务.默认是开启的吗？那为什么还要需要开启了？ 3550(config)#service dhcp //关闭dhcp 客户端IP冲突日志记录信息 3550(config)#no ip dhcp conflict logging //配置地址池名称，地址池名称为任意字符（这里定义的名字VLAN的名称） 3550(config)#ip dhcp pool renshibo //配置PC所获得网段地址范围，和掩码，（这里有几种命令语句格式） (network 192.168.0.0 255.255.255.0) 3550(dhcp-config)#network 192.168.0.0 /24 //配置网关地址 3550(dhcp-config)#default-router 192.168.0.1 //配置DNS（域名解析服务器）可选配置 请问什么时候PC需要配置DNS地址？局域网通讯需要吗？ 3550(dhcp-config)#dns 218.30.19.40 61.134.1.4 //配置域名 3550(dhcp-config)#domain-name www.cisco.com //配置地址租期为永久 3550(dhcp-config)#lease infinite 3550(dhcp-config)#exit //配置排除的IP地址范围，不从地址池内分配的地址，不配置排除地址可以吗？ 3550(config)#ip dhcp excluded-address 192.168.0.1 3550(config)#ip dhcp pool shichangbo 3550(dhcp-config)#network 172.16.0.0 /24 3550(dhcp-config)#default-router 172.16.0.1 3550(dhcp-config)#dns 218.30.19.40 61.134.1.4 3550(dhcp-config)#domain-name www.cisco.com 3550(dhcp-config)#lease infinite 3550(dhcp-config)#exit 3550(config)#ip dhcp excluded-address 172.16.0.1

第五步 在市场部PC上验证是否能从catalyst 3550获得IP地址, 如图：开始-运行-cmd-ipconfig /all
第六步 在Catalyst 3550查看PC获得的IP地址是否正确

//查看DHCP绑定信息 3550#sh ip dhcp binding IP address Client-ID/ （MAC地址） Lease expiration Type Hardware address 172.16.0.2 0100.16d3.249f.fd Infinite Automatic 192.168.0.2 0100.1641.15e8.5c Infinite Automatic

第七步 在交换机测试是否可以ping通市场部和人事部PC

3550(config)#exit 3550# 00:26:41: %SYS-5-CONFIG_I: Configured from console by console 3550#ping 172.16.0.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.16.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms 3550#ping 192.168.0.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.0.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

第八步 在市场部PC上用ping命令测试是否可以ping通VLAN100（人事部） 下PC 如图：测试结果如下，可以ping通，实验现象成功！