監(jiān)測清單4-1 ip address、ip address secondary、show interface等命令
R1# R1#conft Enter configuration commands, one per line. End with CNTL/Z. R1(config)#int e0 R1(config-if)#ip addr 172.16.1.1255.255.255.0 R1(config-if)#no sh R1(config-if)#end R1# 00:51:18: %SYS-5-CONFIG_1: Configured from console by console (鍵入組合鍵Ctrl+shift+6,x,切換回終端服務器) Term_Server>2 [Resuming connection 2 to R2 ... ] R2# R2#conft Enter configuration commands, one per line. End with CNTL/Z. R2(config)#int eO R2(config-if)#ip addr 172.16.1.2 255.255.255.0 R2(config-if)#no sh R2(config-if)#end R2# 00:52:58: %SYS-5-CG_I: Configured from console by console R2#sh int eO Ethernet0 is up, line PRotocol is up Hardware is Internet address is 172.16.1.2/24 MTU 1500 bytes,BW 1000 Kbit,DLY 1000 usec. reliability 255/255,txload 1/255,rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:10, output 00:00:09, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 Queueing strategy:fifo Output queue :0/40 (size/max) 5 minute input rate Orbits/see, ;1:pactets/sec 5 minute output 203 packets input, 29123 bytes, 0 no buffer Received 203 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 input packets with dribble condition detected 382 packets output, 37648 bytes, 0 underruns 0 output errors, 0 collisions, 18 interface resets 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier 0 output buffer failures, 0 output buffers swapped out R2#sh ip int eO EthemetO is up, line protocol is up Internet address is 172.16.1.2.2/24 Broadcast address is 255.255.255.255 Adress determined by setup command MTU is 1500 bytes Helper address is not set Directed broadcast forwarding is desabled lutgoing access list is not set Inbound access list is not set Proxy ARP is enabled security level is default split horion is enabled ICMP redirects are always sent ICMP unreachables are always sent IP fast switching is enabled IP fast switching on the same interface is disabled IP Flow switching is disabled IP Fast switching turbo vector IP multicast fast switching is enabled IP multicast distributed fast switching is disabled IP route-cache flags are Fast Router Discovery is disabled IP output packet accounting is disabled IP access violation accounting is disabled TCP/IP header compression is disabled RTP/IP header compression is disabled Probe proxy name replies are disabled Policy routing is disabled Network address translation is disabled WCCP Redirect outbound is disabled WCCP Redirect exclude is disabled BGP Policy Mapping is disabled R2#SH IP int brief interface IP-Address ok?Method status protocol Ethernet0 170.16.1.2 YES manual up up serial0 unassigned YES NVRAM administratively down down serial1 unassigned YES NVRAM administratively down down R2#ping 172.16.1.1 Type escape sequence to abort. sending 5,100-byte ICMPEchos to 172.16.1.1,timeout is 2 seconds: ..!!! sUCcess rate is 60 percent(3/5),round-trip min/avg/max=4/4/4 ms R2#conft Enter configuration commands,one per line.End winth CNTL/Z R2(config)#ip subnet-zero R2(config)#ing e0 R2(config-if)#ip addr 172.0.0.1 255.255.255.0 Bad mask/24 for address 172.0.0.1 R2(config-if)#exit R2(config)#if subnet-zero R2(config)#int e0 R2(config-if)#ip addr 172.0.0.1255.255.255.0 R2(config-if)#ip addr 172.1.0.1 255.255.255.0 secondary R2(config-if)#ip addr 172.2.0.1 255.255.255.0 secondary R2(config-if)#^Z R2# (1)在監(jiān)測清單的開始部分，分別在Rl和R2路由器的EO接口上配置了相應的IP地址。注重配置好IP地址后立即發(fā)出了Ho shut命令激活接口，初學者往往忽視此命令。 (2)sh int e0命令即show interface e0，其運行結果顯示了EO接口的配置信息和統(tǒng)計信息，其中大部分是統(tǒng)計信息。配置信息有MAC地址(0000。0c8e。cdd2)、IP地址、MTU(15OOBytes)、BW(帶寬，lOMbMs)、DLY(延遲)。reliability(可靠性)以及負載 (txload和rxload)等信息;統(tǒng)計信息是關于隊列(而putqueue、Output queue)、最近5min時間內的輸入、輸出速率及數據包數量等信息。 (3)show ip interface e0(sh ip int eo)命令顯示了EO接口上有關IP的所有配置信息，包括IP地址、廣播地址、MTU、訪問列表。Proxy ARP等眾多條目我們應主要關注與CCNA考試相關的條目。 (4)，show ip interface e0(sh ip int brief)以簡潔的形式列出了路由器所有接口有關IP地址的配置信息，包括接口IP地址、是否可用 (OK?)、IP地址獲取的方式 (Method)。接口狀態(tài)(Status)和協(xié)議狀態(tài)(Protocol)。其中manual表示人工設置，NVRAM表示啟動時從配置文件中獲取。 (5)使用Ping命令測試Rl和R2的IP連通性，以確認配置是否生效。注重ping命令執(zhí)行結果中的細節(jié)，即"..!!!"，這表示前兩個包沒有ping通，這是因為開始時在R2的ARP表中還沒有R1的EO接口相關的表項，即不知道172.16.1.1的MAC地址是什么，在下面關于ARP相關命令的實驗中，這一點會非常清楚地顯示出來。 (6)在IOS11.3以后的版本中，ip subnet-zero語句成為Cisco路由器的缺省配置。它使得零子網成為合法的網絡號。在實驗中，首先關閉了此功能，即發(fā)出命令no ip subnet-zero，當設置EO接口的IP地址為172.0.0.1時，路由器報錯;當發(fā)出命令ip subnet-zero答應零子網存在時，對EO接口重復上述的配置命令時，IP地址被成功設置。 (7)ip addr 172.1.0.1.255.255.255.0 secondary命令為EO接
