任务 1：配置路由器的基本参数，确保网络设备互联
步骤 1：登录到 R1 的命令行界面
步骤 2：出现以下提示，选择“NO”，进入命令行
% Please answer 'yes' or 'no'. Would you like to enter the initial configuration dialog? [yes/no]: no Press RETURN to get started!
步骤 3：进入全局配置模式，配置主机名为 R1
Router>enable Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#hostname R1 R1(config)#
步骤 4：进入 FastEthernet0/0（如果没有 FastEthernet0/0，则进入 Ethernet0/0），配置接口 IP 为 192.168.1.1，掩码为 255.255.255.0，并打开接口
R1(config)#interface FastEthernet 0/0 R1(config-if)#ip address 192.168.1.1 255.255.255.0 R1(config-if)#no shutdown R1(config-if)#exit
步骤 5：进入 R2 的命令行界面，配置主机名为 R2
Router>enable Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#hostname R2
步骤 6：进入 FastEthernet0/0（如果没有 FastEthernet0/0，则进入 Ethernet0/0），配置接口 IP 为 192.168.1.2，掩码为 255.255.255.0，并打开接口
R2(config)#interface fastEthernet 0/0 R2(config-if)#ip address 192.168.1.2 255.255.255.0 R2(config-if)#no shutdown R2(config-if)#exit
步骤 7：进入 R3 的命令行界面，配置主机名为 R3
Router>enable Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#hostname R3
步骤 8：进入 FastEthernet0/0（如果没有 FastEthernet0/0，则进入 Ethernet0/0），配置接口 IP 为 192.168.1.3，掩码为 255.255.255.0，并打开接口
R3(config)#interface fastEthernet 0/0 R3(config-if)#ip address 192.168.1.3 255.255.255.0 R3(config-if)#no shutdown R3(config-if)#exit
步骤 9：检查 3 台路由器的接口状态列表，确保接口的 Line-Protocol 是状态是“UP”，如果在接口开启（no shutdown）的情况下，Line-Protocol 是“Down”，说明该接口的线缆有问题。
R1#show protocols //show ip interface brief 的效果基本一致 Global values: Internet Protocol routing is enabled FastEthernet0/0 is up, line protocol is up Internet address is 192.168.1.1/24 Serial0/0 is administratively down, line protocol is down FastEthernet0/1 is administratively down, line protocol is down Serial0/1 is administratively down, line protocol is down
R2#show protocols Global values: Internet Protocol routing is enabled FastEthernet0/0 is up, line protocol is up Internet address is 192.168.1.2/24 Serial0/0 is administratively down, line protocol is down FastEthernet0/1 is administratively down, line protocol is down Serial0/1 is administratively down, line protocol is down
R3#show protocols Global values: Internet Protocol routing is enabled FastEthernet0/0 is up, line protocol is up Internet address is 192.168.1.3/24 Serial0/0 is administratively down, line protocol is down FastEthernet0/1 is administratively down, line protocol is down Serial0/1 is administratively down, line protocol is down
步骤 10：使用 ping，测试 3 台路由器的互相连通性，请确保 3 台路由器之间都能互相通信
R1#ping 192.168.1.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds: .!!!! Success rate is 80 percent (4/5), round-trip min/avg/max = 1/1/1 ms
R1#ping 192.168.1.3 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.1.3, timeout is 2 seconds: .!!!! Success rate is 80 percent (4/5), round-trip min/avg/max = 1/1/4 ms
R2#ping 192.168.1.3 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.1.3, timeout is 2 seconds: .!!!! Success rate is 80 percent (4/5), round-trip min/avg/max = 1/1/4 ms
提问：为什么 R3 不用测试？