本实验以WS-3550-48 SMI为例,详细描述对于2900xl/3500xl/2950/3550系列交换机的密码恢复流程
一、将一台终端或装有超级终端软件的PC接到交换机的console口上。终端参数设置如下:
速率:9600bps
校验位:无
数据位:8
停止位:1
流控:无
二、拨掉电源
三、按住前面板的mode键不放,插上电源,等35秒后松开mode键。你会看到如下提示:
Interrupt within 5 seconds to abort boot process.
Boot process terminated.
The system is unable to boot automatically.  The BOOT
environment variable needs to be set to a bootable
image.
switch:
switch: ?
           ? -- Present list of available commands
        boot -- Load and boot an executable image
         cat -- Concatenate (type) file(s)
        copy -- Copy a file
      delete -- Delete file(s)
         dir -- List files in directories
  flash_init -- Initialize flash filesystem(s)
      format -- Format a filesystem
        fsck -- Check filesystem consistency
        help -- Present list of available commands
 load_helper -- Load and initialize a helper image
      memory -- Present memory heap utilization information
       mkdir -- Create dir(s)
        more -- Concatenate (display) file(s)
      rename -- Rename a file
       reset -- Reset the system
       rmdir -- Delete empty dir(s)
         set -- Set or display environment variables
   set_param -- Set system parameters in flash
       sleep -- Pause (sleep) for a specified number of seconds
        trap -- Cause a software breakpoint to occur
 -- MORE --
        type -- Concatenate (type) file(s)
       unset -- Unset one or more environment variables
四、输入flash_init       //初始化flash文件系统
五、输入load _helper   
六、输入dir flash:
注意,不要少了flash后面的冒号,屏幕出现如下提示。
Directory of flash:/
3    -rwx  0         <date>               env_vars
4    -rwx  344       <date>               system_env_vars
5    -rwx  3624      <date>               config.text
6    -rwx  5         <date>               private-config.text
8    drwx  192       <date>               c3550-i9q3l2-mz.121-14.EA1a
86   -rwx  5         <date>               private-config.text.renamed
10243584 bytes available (5755392 bytes used)
七、输入rename flash:config.text flash:config.old
switch: rename flash:config.text flash:config.old
八、输入boot引导系统。
switch: boot
Loading "flash:c3550-i9q3l2-mz.121-14.EA1a/c3550-i9q3l2-mz.121-14.EA1a.bin"...##############################################################################################################################################################################################################################################################################################################################################################################################################
File "flash:c3550-i9q3l2-mz.121-14.EA1a/c3550-i9q3l2-mz.121-14.EA1a.bin" uncompressed and installed, entry point: 0x3000
executing...

九、当出现如下提示时,输入N
Continue with the configuration dialog? [yes/no] : N
十、用en进入enable状态,并将文件config.old改回config.text,命令如下:
rename flash:config.old flash:config.text
十一、将原配置装入内存,命令如下:
switch# copy flash:config.text system:running-config
十二、修改密码:
switch#conf t