If you are like me, you tend to click things just to see how they work. Sometimes they don’t work. At all. If you’ve mucked up the IP, vlan, etc settings and the Cisco ASDM can’t get into the device, it’s time for more desperate measures. If you can get into the ASDM, it is easier to Reset to Factory Defaults using the Cisco’s ASDM.

There is a button on the back of the device that says ‘Reset’. This button appears to be entirely for looks.

1. hook up the blue console cable to your serial port, plugging the other end into ‘Console’ port on the ASA 5505. The console port looks like a network jack, but it’s above the usb ports.
2. Select a terminal program.
   1. In Windows XP, use hyperterminal, click Start, Programs, Accessories, Communications, Hyperterminal, create a connection on Com1 using the terminal settings:
   2. In Windows 7, I recommend Putty. Download and install it, then make a new connection. Select the radio Type: Serial, then click Serial on the left and use these settings:
   • Bits per second: 9600
   • Data bits: 8
   • Parity: None
   • Stop bits: 1
   • Flow control: None
3. After you open your connection, press enter a couple times, and you should get a prompt like: ‘ciscoasa>’, or ‘nameofyourdevice>’
4. type ‘ena’ to go to enable mode. Enter the password, or just press enter if there is no password set.
5. type ‘config t’
6. type ‘config factory-default’
7. hit spacebar when the ‘more’ thing happens. You want to get back to the prompt that looks like: ‘ciscoasa(config)#’
8. type ‘reload save-config noconfirm’
9. make sure that the outside line is plugged into port zero, and your pc is plugged into any of the ports 1-7.
10. The Cisco ASA has been reset to factory settings. DHCP is enabled on the cisco device, and it’s internal IP address is now 192.168.1.1!
11. If you had an enable password set, you may need to enter that in the password box when you try to connect using the ASDM. Otherwise the default username and password is to leave both blank.