1.首先需要到天空软件站下载“Cisco TFTP Server”，作为防火墙从电脑提取密码恢复文件之用；以及到思科网站下载密码恢复文件“np70.bin”，网址是http://www.cisco.com/en/US/products/hw/***devc/ps2030/products_password_recovery09186a008009478b.shtml
2.使用配置线连接电脑串口和防火墙console口，用于通过“超级终端”配置防火墙；此外需要一条交叉网线连接电脑网口和防火墙ethernet0口，用于防火墙从TFTP Server获取“np70.bin”。
3.将电脑ip设为：
10.67.207.120
255.255.255.0
10.67.207.1
4.运行“思科 TFTP 服务器”，无需任何设置，直接将其最小化。
5.运行“超级终端”，在com1属性端口设置中点“还原为默认值”，再点确定，此时已经进入了用户模式pixfirewall>。如看不到提示符，可按一下回车键。
6.重启防火墙，在屏幕上出现倒计时的时候马上按Ctrl+Break键，进入到ROM监视模式monitor>。
7.以下是对防火墙的配置过程：
monitor> interface 0
0: i8255X @ PCI(bus:0 dev:14 irq:10)
1: i8255X @ PCI(bus:0 dev:13 irq:11)
Using 0: i82557 @ PCI(bus:0 dev:14 irq:10), MAC: 001c.58b5.73b8
monitor> address 10.67.207.1
address 10.67.207.1
monitor> server 10.67.207.120
server 10.67.207.120
monitor> file np70.bin
file np70.bin
monitor> ping 10.67.207.120
Sending 5, 100-byte 0x9480 ICMP Echoes to 10.67.207.120, timeout is 4 seconds:
!!!!!
Success rate is 100 percent (5/5)
monitor> tftp
tftp [email protected].....................................................
................................................................................
................................................................................
........................................
Received 129024 bytes
Cisco PIX Security Appliance password tool (3.0) #0: Thu Jun 9 21:45:44 PDT 2005
Initializing flashfs...
flashfs[0]: 6 files, 3 directories
flashfs[0]: 0 orphaned files, 0 orphaned directories
flashfs[0]: Total bytes: 16128000
flashfs[0]: Bytes used: 5131264
flashfs[0]: Bytes available: 10996736
flashfs[0]: Initialization complete.
Using the default startup configuration
Do you wish to erase the passwords? y/n [n]: y
The following lines will be removed from the configuration:
enable password M6j8Z8OZss573zTI encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
Do you want to remove the commands listed above from the configuration? y/n [n]y
Passwords and aaa commands have been erased.
Rebooting....
8.最后验证一下：
pixfirewall> enable
Password: //密码为空，直接回车
pixfirewall# //成功了!!