Clearing, resetting or erasing configuration on Cisco ASA

There are multiple different ways to do that but I prefer this two ways to clear my configuration from ASA.

First [ciscoasa# write erase] and second [ciscoasa(config)# configure factory-default]

There is option for configure factory-default command:

configure mode commands/options:

  Hostname or A.B.C.D  Specify optional management interface IP address

Which one to use, well, both does their job quite good. Clear configuration file to the basic configuration of ASA.

 

If your goal is to have ASA configured just like out of box from Cisco go with [ciscoasa(config)# configure factory-default]

You will get configured DHCP Server configured for INSIDE hosts, all interfaces will be in vlan 1, OUTSIDE interface vlan 2 will be set with command [ip address dhcp setroute], you will get object network, configured with NAT, ACL etc. Something likes plug-and-play for SOHO.

Note: The boot system configuration will be cleared. The first image found in disk0:/ will be used to boot the system on the next reload. Verify there is a valid image on disk0:/ or the system will

not boot.

With [ciscoasa# write erase] you will erase configuration file in flash startup-configuration.

ciscoasa# write erase

Erase configuration in flash memory? [confirm]

[OK]

After this use reload on ASA.

You will get cleared ASA configuration file, without DHCP Server any interface configured no ip addresses or NAT as you will get with factory default restart.

NOTE: Always backup your configurations and your images, never do anything that you can’t undo.