RT1 enable conf t /进入全局模式 banner motd #this is a ccna1# /设置旗标 banner login #this is a ccna1# int f0/0 /进入接口 ip add 172.16.20.1 255.255.255.0 /接口配ip地址 int f0/1 ip add 172.16.10.1 255.255.255.0 eixt ip route 172.16.30.0 255.255.255.0 172.16.20.2 /配置路由信息，30网段的地址指向172.16.20.2这个接口 ip route 172.16.40.0 255.255.255.0 172.16.20.2 ip route 172.16.50.0 255.255.255.0 172.16.20.2 exit write RT2 enable conf t banner motd #this is a ccna2# banner login #this is a ccna2# ip route 172.16.10.0 255.255.255.0 172.16.20.2 ip route 172.16.40.0 255.255.255.0 172.16.30.2 exit write RT3 enable conf t banner motd #this is a ccna3# banner login #this is a ccna3# ip route 172.16.10.0 255.255.255.0 172.16.30.1 ip route 172.16.20.0 255.255.255.0 172.16.30.1 ip route 172.16.50.0 255.255.255.0 172.16.30.1 exit write pc1 ip 172.16.10.3/24 172.16.10.1 /配置IP地址、掩码和网关 pc2 ip 172.16.50.2/24 172.16.50.1 pc1 ip 172.16.40.2/24 172.16.40.1 路由器替代pc ip route 172.16.20.0 255.255.255.0 172.16.10.1 ip route 172.16.30.0 255.255.255.0 172.16.10.1 ip route 172.16.40.0 255.255.255.0 172.16.10.1 ip route 172.16.50.0 255.255.255.0 172.16.10.1 /配置路由 或者：配置默认路由 0.0.0.0 0.0.0.0 172.16.10.1
