破解密码原则：只删除密码 ，不破坏配置
#本文中的#号表示注释的意思
#第一步. 连接交换机的console口到终端
#第二步. 按住交换机面板上的mode键的同时 插入电源，直到sys灯不闪，常亮再松开mode键

C2950 Boot Loader (C2950-HBOOT-M) Version 12.1(6)EA2c, RELEASE SOFTWARE (fc1)                                                                            
Compiled Thu 28-Feb-02 14:59 by antonino                                       
WS-C2950C-24 starting...                       
Base ethernet MAC Address: 00:09:e8:b4:45:40                                           
Xmodem file system is available.                               

The system has been interrupted prior to initializing the                                                        
flash filesystem.  The following commands will initialize                                                        
the flash filesystem, and finish loading the operating                                                     
system software:               

    flash_init             
    load_helper              
    boot  
----------------------------------    

#
#flash_init   :初始化flash文件系统
#load_helper  :加载帮助文件
#boot         :启动设备进入正常的模式

#第三步 这里我们选择初始化 flash
Initializing Flash...                    
flashfs[0]: 17 files, 2 directories                                  
flashfs[0]: 0 orphaned files, 0 orphaned directories                                                   
flashfs[0]: Total bytes: 7741440                               
flashfs[0]: Bytes used: 4502528                              
flashfs[0]: Bytes available: 3238912                                   
flashfs[0]: flashfs fsck took 7 seconds.                                       
...done initializing flash.                          
Boot Sector Filesystem (bs:) installed, fsid: 3                                              
Parameter Block Filesystem (pb:) installed, fsid: 4
switch: rename flash:config.text flash:config.old
#第四步 改名含有password的配置文件
switch: boot

#第五步 启动交换机
Loading "flash:c2950-i6q4l2-mz.121-9.EA1.bin"...################################         
Done initializing flashfs.                         
POST: System Boa
##################################################ST: Ethernet Controller                        
nt: 0x80010000 interface(s)
executing...           

              Restricted Rights Legendted non-volatile configuration memory.

Use, duplication, or disclosure by the Government is        
Base ethernet MAC Address: 00:09:E8:B4:45:
subject to restrictions as set forth in subparagraphboard assembly number: 73-5750-10                  
(c) of the Commercial Computer Software - Restricted5-01                                   
Motherboard
Rights clause at FAR sec. 52.227-19 and subparagraph           
Power supply serial n                 
           170 West Tasman Drive type vlan                     
           San Jose, California 95134-1706        
00:00:17: %SYS-5-CONFIG_I: Confi

Cisco Internetwork Operating System Software                                       
00:
IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(9)EA1, RELEASE SOFTWARE (     
Cisco Internetwork Operating System Software                            
fc1)   
Copyright (c) 1986-2002 by cisco Systems, Inc., Version 12.1(9)EA1, RELEASE SOFTWARE (     
Compiled Wed 24-Apr-02 06:57 by antonino                                
fc1) 
Image text-base: 0x80010000, data-base: 0x804E8000                                           
Compi

Initializing flashfs... antonino             
flashfs[1]: flashfs fsck took 7 seconds.40                                     
flashfs[1]: Initialization complete.e.                               
I
Done initializing flashfs.             
flashfs[0]:
POST: System Board Test : Passed                         
flash
POST: Ethernet Controller Test : Passedctories                               
ASIC Initialization Passeds[0]: Total bytes: 7741440

POST: FRONT-END LOOPBACK TEST : Passed[0]: Bytes used: 4502528             
cisco WS-C2950C-24 (RC32300) processor (revision E0) with 20815K bytes of memory        
flashfs[0]: flashfs fsck took 6 second                               
.
Base ethernet MAC Address: 00:09:E8:B4:45:40############################################
Motherboard assembly number: 73-5750-10                                      
Power supply part number: 34-0965-01
###################################
Motherboard serial number: FOC062403UM######                               
System serial number: FOC0624X14E

         --- System Configuration Dialog ---

#########################################################################

Current configuration : 1522 bytes                                 
!

Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.

Switch(config)#username root password cisco
Switch(config)#enable secret cisco
Switch(config)#line cons 0
Switch(config-line)#pass cisco
Switch(config-line)#login
Switch(config-line)#exit
Switch(config)#
-------------

Switch(config)#exit
Switch#
00:05:47: %SYS-5-CONFIG_I: Configured from console by console
Switch#copy run start

Destination filename [startup-config]?
Building configuration...
[OK]
Switch#
-=--------
Switch#reload
#重新启动

-----------

Press RETURN to get started!

00:00:14: %SPANTREE-5-EXTENDED_SYSID: Extended SysId enabled for type vlan
00:00:17: %SYS-5-CONFIG_I: Configured from memory by console
00:00:17: %SYS-5-RESTART: System restarted --
Cisco Internetwork Operating System Software
IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(9)EA1, RELEASE SOFTWARE (
fc1)
Copyright (c) 1986-2002 by cisco Systems, Inc.
Compiled Wed 24-Apr-02 06:57 by antonino
00:00:18: %LINK-5-CHANGED: Interface Vlan1, changed state to administratively do
wn
00:00:19: %LINEPRO

User Access Verification

Password: TO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
Password:
Switch>en
Password:
Switch#