CISCO 端口检测常用命令

作者: admin 分类: 乱7八糟 发布时间: 2010-08-27 04:25 ė 6 没有评论

下面以Cisco1800路由器为例,介绍一下常用的查看端口和通道状况的命令。 在MS-DOS窗口里敲入命令telnet+IP地址,回车,即可远程登录路由器。一般用路由器局域网口地址。 1,用R1#sh ip int b命令查看端口状态 R1#sh ip int b Interface IP-Address OK? Method Status Protocol FastEthernet0/0 100.100.100.226 YES NVRAM up up FastEthernet0/1 200.200.200.226 YES NVRAM up up Serial0/0/0 72.22.81.102 YES NVRAM up up Serial0/0/1 72.22.81.109 YES NVRAM up up 正常情况下,思科1800路由器四个端口的Status和protocol都是up的。 2,用R1#sh int s0/0/0查看链路状态和通道情况 Serial0/0/0 is up, line protocol is up //接口与协议都已启动(正常) Serial0/0/0 is up, line protocol is down //接口启动,协议没有匹配成功(端口无物理故障,但通道不通) Serial0/0/0 is down, line protocol is down (notconnect)//接口与协议都DOWN掉,本端端口没有与对方建立物理连接,可能是对方设备没有开启,对方端口故障或者线路故障造成。 Serial0/0/0 is down, line protocol is down //接口与协议都DOWN掉(协转没有工作) Serial0/0/0 is down,line protocol is down(disable)//端口出现物理性故障,需更换端口。 Serial0/0/0 is administratively down,line protocol is down //接口关闭,可用命令打开。 Serial0/0/0 is up, line protocol is down(looped) //此通道上有环(无论在协转、DDF架、SDH上做环,在路由器里看到的显示是一样的)。 Serial0 is up, line protocol is down Hardware is PowerQUICC Serial Interface is unnumbered. Using address of FastEthernet0/0 (172.22.128.193) MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 //通道的可靠性 Encapsulation PPP, LCP Listen, loopback not set Last input 00:00:27, output 00:00:27, output hang never Last clearing of “show interface” counters 00:02:52 //上次计数器清零到现在的时间 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/2/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) Available Bandwidth 1158 kilobits/sec 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 30 packets input, 420 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 6552 input errors, 0 CRC, 4 frame, 0 overrun, 0 ignored, 0 abort// 输入错误包数量 60 packets output, 840 bytes, 0 underruns 0 output errors, 0 collisions, 9 interface resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up 通道的可靠性,正常值是255/255,如果低于254将会造成丢包。可靠性越低,通道越差,错误包越多。 DCD 数据载体检测DTE CARrfer derect DSR 数据设置就绪DATA SET READY DTR 数据终端就绪DTE IS READY RTS 请求发送Reguest To Send CTS 清除发送Clear To send 3,路由器端口计数器清零有故障的通道往往造成路由器接口的输入错误包数量很高,不便于比较查看。这时最好把接口数据包计数器清零,使其重新开始计数。用R1#clear coun命令清零。 R1#clear coun 4,判断以太网端口故障用R1#sh int f0/0 来检查以太网口及其链路的状态,如下所示: R1#sh int f0/0 FastEthernet 0 is up,line protocol is up //连接正常 Ethernet 0 is up,line protocol is down //连接故障,路由器没有连接到局域网 Ethernet 0 is down,line protocol is down(disable) //接口故障 Ethernet 0 is administratively down,line protocol is down //接口被关闭,可用命令打开 5,查看相邻路由器用R2#sh cdp nei命令查看相邻路由器,输出如下: R2#sh cdp nei Capability Codes: R – Router, T – Trans Bridge, B – Source Route Bridge S – Switch, H – Host, I – IGMP, r – Repeater Device ID Local Intrfce Holdtme Capability Platform Port ID R1 Ser 0/0/0 133 R S I 1841 Ser 0/0/1 S2_SW1 Fas 0/0 125 S I WS-C2960-2Fas 0/6 S2_SW2 Fas 0/1 140 S I WS-C2960-2Fas 0/22 R3 Ser 0/0/1 156 R S I 1841 Ser 0/0/0 此命令可以查看到相邻的思科路由器和思科交换机,可以验证设备是否相通,以及连接关系是否正确。 6,观察路由器告警和报错信息路由器发生故障或状态发生变化的时候,会发出告警、报错、提示信息。如果是用telnet命令登录路由器的话,不能直接看到这些信息,需要输入R1# ter mon命令后,才能使这些信息显示在MS-DOS窗口上。 R1#ter mon 该命令可以使你及时了解路由器状态变化,便于发现和排除故障。

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