If you have been mucking around in your Cisco ASA5505 and want to return to factory defaults using the ASDM management software, it’s pretty easy.
If you can’t use the ASDM, I have also have a write up for Resetting the Cisco asa 5505 Using the Console.
- Click the “Wizards” drop down menu and select “Startup Wizard…”
- Change the radio button to “Reset configuration to factory defaults.”
- I suggest changing the management IP. This will change the subnet of devices behind the firewall. This is useful if you ever have to put another firewall device behind this device as some consumer grade devices make it a pain to change the internal subnet. You can use any non-routable IP, such as 192.168.x.1 where x is 1-254.
- Click “Yes.”
- After a few minutes, I got a status message with an ERROR. This is because the ASDM is trying to manage the device using the old IP.
- Close the ASDM without saving, renew you DHCP lease and log in using the ASDM to the new address.
- This doesn’t seem to reset the Enable password, so you’ll have to use that to login.