ROM 功能ROM 存放完成基本功能的微代码 Bootstrap Mini IOS ROM monitor POST show version 控制台
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确认当前的配置寄存器值 wg_ro_a# showversion Cisco Internetwork Operating System Software IOS (tm) 2500 Software (C2500-JS-L), Version 12.0(3), RELEASE SOFTWARE (fc1) Copyright (c) 1986-1999 by cisco Systems, Inc. Compiled Mon 08-Feb-99 18:18 by phanguye Image text-base: 0x03050C84, data-base: 0x00001000 ROM: System Bootstrap, Version 11.0(10c), SOFTWARE BOOTFLASH: 3000 Bootstrap Software (IGS-BOOT-R), Version 11.0(10c), RELEASE SOFTWARE (fc1) wg_ro_a uptime is 20 minutes System restarted by reload System image file is "flash:c2500-js-l_120-3.bin" --More-- Configuration register is 0x2102 用命令 show version 所显示的配置寄存器值
使用 showrunning 和 show startup 命令 wg_ro_c# show startup-config Using 1359 out of 32762 bytes ! version 12.0 ! -- More -- wg_ro_c # show running-config Building configuration... Current configuration: ! version 12.0 ! -- More -- 存在 NVRAM 中 存在 RAM 中 显示当前运行的和保存的配置情况
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路由器启动流程图 Use IOSfrom Flash Attempt to get IOS from network Use IOS in ROM (RXBoot mode) Check start-up config Boot field =0 0x0 Boot field =1 0x1 Boot system commands ? Config reg bit 13=1 ? 5 failures ? Valid IOS in Flash ? Do what they say Run ROM Monitor START Yes Yes No No Yes No No Yes Yes No No Yes Success ? No Yes Use file from Network Load IOS Valid config ? Config reg bit 6=1 ? Yes No Yes SETUP DIALOG NORMAL START UP COMPLETE No
查看寄存器值; Router#showversion ROM: System Bootstrap, Version 5.2(8a), RELEASE SOFTWARE BOOTFLASH: 3000 Bootstrap Software (IGS-RXBOOT), Version 10.2(8a), RELEASE SOFTW ARE (fc1) RouterA uptime is 11 minutes System restarted by power-on System image file is "flash:c2500-d-l_113-5.bin", booted via flash Bridging software. X.25 software, Version 3.0.0. 1 Ethernet/IEEE 802.3 interface(s) 2 Serial network interface(s) 32K bytes of non-volatile configuration memory. 8192K bytes of processor board System flash (Read ONLY) Configuration register is 0x2102 注意:三个常用的寄存器值, 0x2102 正常启动,调用 NVRAM 配置信息; 0x2142 跳过 NVRAM 启动路由器 ;0x2101 Read/Write ,可擦写模式。
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启动路由器,进入 ROMMON 模式 打开路由器,按下 ctrl + break 键,进入监视模式 System Bootstrap, Version 5.2(5), RELEASE SOFTWARE Copyright (c) 1986-1994 by cisco Systems 2500 processor with 16384 Kbytes of main memory Abort at 0x10201A2 (PC) >
使用 CDP交换机 B 路由器 A 路由器 B 交换机 A 10.3.3.2 10.3.3.1 10.1.1.1 10.1.1.2 10.2.2.1 10.2.2.2 S0 S1 RouterA#sh cdp ? entry Information for specific neighbor entry interface CDP interface status and configuration neighbors CDP neighbor entries traffic CDP statistics <cr> RouterA(config)#no cdp run RouterA(config)#interface serial0 RouterA(config-if)#no cdp enable
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使用 show cdpneighbor 命令 交换机 A 同时也显示其 Mac 地址 RouterA#sh cdp neighbors 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 RouterB Ser 0 148 R 2522 Ser 1 SwitchA0050BD855780 Eth 0 167 T S 1900 2 10.3.3.2 10.3.3.1 10.1.1.1 10.1.1.2 10.2.2.1 10.2.2.2 S0 S1 交换机 B 路由器 A 路由器 B 交换机 A
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使用 show cdpentry 命令 RouterA#sh cdp entry * ------------------------- Device ID: RouterB Entry address(es): IP address: 10.1.1.2 Platform: cisco 2522, Capabilities: Router Interface: Serial0, Port ID (outgoing port): Serial1 Holdtime : 168 sec Version : Cisco Internetwork Operating System Software IOS (tm) 2500 Software (C2500-JS-L), Version 12.0(3), RELEASE SOFTWARE (fci) Copyright (c) 1986-1999 by cisco Systems, Inc. Compiled Mon 08-Feb-99 18:18 by phanguye 10.3.3.2 10.3.3.1 10.1.1.1 10.1.1.2 10.2.2.1 10.2.2.2 S0 S1 交换机 B 路由器 A 路由器 B 交换机 A
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其它 CDP 命令RouterA#sh cdp traffic CDP counters : Packets output: 56, Input: 38 Hdr syntax: 0, Chksum error: 0, Encaps failed: 3 No memory: 0, Invalid packet: 0, Fragmented: 0 RouterA#sh cdp interface BRI0 is administratively down, line protocol is down Encapsulation HDLC Sending CDP packets every 60 seconds Holdtime is 180 seconds 10.3.3.2 10.3.3.1 10.1.1.1 10.1.1.2 10.2.2.1 10.2.2.2 S0 S1 交换机 B 路由器 A 路由器 B 交换机 A
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用 Telnet 连接到远端设备 远端设备 10.3.3.2 10.3.3.1 10.1.1.1 10.1.1.2 10.2.2.1 10.2.2.2 S0 S1 RouterA#telnet 10.2.2.2 Trying 10.2.2.2 ... Open ------------------------------------------------- Catalyst 1900 Management Console Copyright (c) Cisco Systems, Inc. 1993-1998 All rights reserved. Enterprise Edition Software Ethernet Address: 00-90-86-73-33-40 PCA Number: 73-2239-06 PCA Serial Number: FAA02359H8K Model Number: WS-C1924-EN System Serial Number: FAA0237X0FQ . . SwitchB> 交换机 B 路由器 A 路由器 B 交换机 A
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查看 Telnet 连接10.3.3.2 10.3.3.1 10.1.1.1 10.1.1.2 10.2.2.1 10.2.2.2 S0 S1 RouterA#sh session Conn Host Address Byte Idle Conn Name 1 10.1.1.2 10.1.1.2 0 1 10.1.1.2 * 2 10.3.3.2 10.3.3.2 0 0 10.3.3.2 RouterA#sh user Line User Host(s) Idle Location * 0 con 0 10.1.1.2 3 10.3.3.2 2 11 vty 0 idle 1 10.1.1.2 交换机 B 路由器 A 路由器 B 交换机 A
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挂起一个 Telnet 会话10.3.3.2 10.3.3.1 10.1.1.1 10.1.1.2 10.2.2.1 10.2.2.2 S0 S1 RouterB#<Ctrl-Shift-6>x RouterA#sh session Conn Host Address Byte Idle Conn Name 1 10.1.1.2 10.1.1.2 0 1 10.1.1.2 RouterA#resume 1 RouterB# 交换机 B 路由器 A 路由器 B 交换机 A
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关闭一个 Telnet 会话RouterA#disconnect Closing connection to 10.3.3.2 [confirm] RouterA#clear line 11 [confirm] [OK] 关闭由远端设备建立的会话 关闭由自己建立的当前会话 10.3.3.2 10.3.3.1 10.1.1.1 10.1.1.2 10.2.2.1 10.2.2.2 S0 S1 交换机 B 路由器 A 路由器 B 交换机 A
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使用 ping 和 trace 命令 测试对远端设备的连接性和路径 Router## ping 10.1.1.10 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.1.10, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms Router# trace 10.1.1.10 Type escape sequence to abort. Tracing the route to 10.1.1.10 1 10.1.1.10 4 msec 4 msec 4 msec Router#