比较全面的三层交换机配置实例(带命令解释哟!)Enable //进入私有模式Configure terminal //进入全局模式service password-encryption //对密码进行加密hostname Catalyst 3550-12T1 //给三层交换机定义名称enable password 123456. //enable密码Enable secret 654321 //enable的加密密码（应该是乱码而不是654321这样）Ip subnet-zero //允许使用全0子网（默认都是打开的）Ip name-server 172.16.8.1 172.16.8.2 //三层交换机名字Catalyst 3550-12T1对应的IP地址是172.16.8.1Service dhcp //提供DHCP服务ip routing //启用三层交换机上的路由模块ExitVtp mode server //定义VTP工作模式为sever模式Vtp domain centervtp //定义VTP域的名称为centervtpVlan 2 name vlan2 //定义vlan并给vlan取名（如果不取名的话，vlan2的名字应该是vlan002）Vlan 3 name vlan3Vlan 4 name vlan4Vlan 5 name vlan5Vlan 6 name vlan6Vlan 7 name vlan7Vlan 8 name vlan8Vlan 9 name vlan9Exitinterface Port-channel 1 //进入虚拟的以太通道组1switchport trunk encapsulation dot1q //给这个接口的trunk封装为802.1Q的帧格式switchport mode trunk //定义这个接口的工作模式为trunkswitchport trunk allowed vlan all //在这个trunk上允许所有的vlan通过Interface gigabitethernet 0/1 //进入模块0上的吉比特以太口1switchport trunk encapsulation dotlq //给这个接口的trunk封装为802.1Q的帧格式switchport mode trunk //定义这个接口的工作模式为trunkswitchport trunk allowed vlan all //在这个trunk上允许所有的vlan通过channel-group 1 mode on //把这个接口放到快速以太通道组1中Interface gigabitethernet 0/2 //同上switchport trunk encapsulation dotlqswitchport mode trunkswitchport trunk allowed vlan allchannel-group 1 mode onport-channel load-balance src-dst-ip //定义快速以太通道组的负载均衡方式（依*源和目的IP的方式）interface gigabitethernet 0/3 //进入模块0上的吉比特以太口3switchport trunk encapsulation dotlq //给trunk封装为802.1Qswitchport mode trunk //定义这个接口的工作模式为trunkswitchport trunk allowed vlan all //允许所有vlan信息通过interface gigabitethernet 0/4 //同上switchport trunk encapsulation dotlqswitchport mode trunkswitchport trunk allowed vlan allinterface gigbitethernet 0/5 //同上switchport trunk encapsulation dotlqswitchport mode trunkswitchport trunk allowed vlan allinterface gigbitethernet 0/6 //同上switchport trunk encapsulation dotlqswitchport mode trunkswitchprot trunk allowed vlan allinterface gigbitethernet 0/7 //进入模块0上的吉比特以太口7Switchport mode access //定义这个接口的工作模式为访问模式switchport access vlan 9 //定义这个接口可以访问哪个vlan（实际就是分配这个接口到vlan）no shutdownspanning-tree vlan 6-9 cost 1000 //在生成树中，vlan6-9的开销定义为10000interface range gigabitethernet 0/8 – 10 //进入模块0上的吉比特以太口8,9,10switchport mode access //定义这些接口的工作模式为访问模式switchport access vlan 8 //把这些接口都分配到vlan8中no shutdownspanning-tree portfast //在这些接口上使用portfast（使用portfast以后，在生成树的时候不参加运算，直接成为转发状态）interface gigabitethernet 0/11 //进入模块0上的吉比特以太口11switchport trunk encapsulation dotlq //给这个接口封装为802.1Qswitchport mode trunk //定义这个接口的工作模式为trunkswitchport trunk allowed vlan all //允许所有vlan信息通过interface gigabitethernet 0/12 //同上switchport trunk encapsulation dotlqswitchport mode trunkswitchport trunk allowed vlan allinterface vlan 1 //进入vlan1的逻辑接口（不是物理接口，用来给vlan做路由用）ip address 172.16.1.7 255.255.255.0 //配置IP地址和子网掩码no shutdownstandby 1 ip 172.16.1.9 //开启了冗余热备份（HSRP），冗余热备份组1，虚拟路由器的IP地址为172.16.1.9standby 1 priority 110 preempt //定义这个三层交换机在冗余热备份组1中的优先级为110，preempt是用来开启抢占模式interface vlan 2 //同上ip address 172.16.2.252 255.255.255.0no shutdownstandby 2 ip 172.16.2.254standby 2 priority 110 preemptip access-group 101 in //在入方向上使用扩展的访问控制列表101interface vlan 3 //同上ip address 172.16.3.252 255.255.255.0no shutdownstandby 3 ip 172.16.3.254standby 3 priority 110 preemptip access-group 101 ininterface vlan 4 //同上ip address 172.16.4.252 255.255.255.0no shutdownstandby 4 ip 172.16.4.254standby 4 priority 110 preemptip access-group 101 ininterface vlan 5ip address 172.16.5.252 255.255.255.0no shutdownstandby 5 ip 172.16.5.254standby 5 priority 110 preemptip access-group 101 ininterface vlan 6ip address 172.16.6.252 255.255.255.0no shutdownstandby 6 ip 172.16.6.254standby 6 priority 100 preemptinterface vlan 7ip address 172.16.7.252 255.255.255.0no shutdownstandby 7 ip 172.16.7.254standby 7 priority 100 preemptinterface vlan 8ip address 172.16.8.252 255.255.255.0no shutdownstandby 8 ip 172.16.8.254standby 8 priority 100 preemptinterface vlan 9ip address 172.16.9.252 255.255.255.0no shutdownstandby 9 ip 172.16.9.254standby 9 priority 100 preemptaccess-list 101 deny ip any 172.16.7.0 0.0.0.255 //扩展的访问控制列表101access-list 101 permit ip any anyInterface vlan 1 //进入vlan1这个逻辑接口Ip helper-address 172.16.8.1 //可以转发广播（helper－address的作用就是把广播转化为单播，然后发向172.16.8.1）Interface vlan 2Ip helper-address 172.16.8.1Interface vlan 3ip helper-address 172.16.8.1interface vlan 4ip helper-address 172.16.8.1interface vlan 5ip helper-address 172.16.8.1interface vlan 6ip helper-address 172.16.8.1interface vlan 7ip helper-address 172.16.8.1interface vlan 9ip helper-address 172.16.8.1router rip //启用路由协议RIPversion 2 //使用的是RIPv2，如果没有这句，则是使用RIPv1network 172.16.0.0 //宣告直连的网段exitip route 0.0.0.0 0.0.0.0 172.16.9.250 //缺省路由，所有在路由表中没有办法匹配的数据包，都发向下一跳地址为172.16.9.250这个路由器line con 0line aux 0line vty 0 15 //telnet线路（路由器只有5个，是0-4）password 12345678 //login密码loginendcopy running-config startup-config 保存配置。