FWSM IOS upgrade

If you need to upgrade the IOS on a FWSM (Firewall Switch Module), you will soon find out, that the upgrade works slightly different to routers. You don’t have the option of using multiple ‘boot system’ commands, nor can you copy more than one IOS image to the FWSM flash. But then what about failback, if you don’t have the old/current IOS version? (and no you can’t just tftp/ftp the current image from a FWSM when in-use). So now what?

A really neat yet fairly undocumented feature is how the FWSM  addresses the space allocation of the Flash memory. Refer to the application partitions (cf:4 and cf:5), see a previous post that listed the partition break down.

Application Partition cf:4 is used by default,  but cf:5 not.  Because cf:5 provides a secondary partition to boot from,  it allows you to test config on a new IOS version. If you boot of cf:5 appose to cf:4, you have a clean and fresh ‘dir flash:‘ to load a new IOS image on, while leaving the working ‘dir flash:‘ intact .

Just change the default boot partition to cf:5 from the switch, with
boot device module {MOD-NUMBER} cf:5

Then reload the module, and load the ‘test’ IOS image to flash (now cf:5) and do any tests necessary. Once happy remove the above command and upgrade to the new IOS on the default partition cf:4.


FWSM – Reset passwords and AAA

Password recovery on a router is easy, and it is even easier to find the steps if you dont know.

What if you forget the login and enable passwords, or you created a lockout situation because of AAA settings on a FWSM (Firewall Switch Module) blade inside a Cisco 6500 or Cisco 7600?

You have two options.

  1. The Cisco way
  2. The Alternative way (as always)

The Cisco way is not hard but needs understanding of the hardware. The FWSM has a 128-MB Flash memory card that stores the operating system, configurations, and other data. The Flash memory includes six partitions, referenced as ‘cf:n‘.

  • Maintenance partition (cf:1) — Contains the maintenance software.
  • Network configuration partition (cf:2) — Contains the network configuration of the maintenance software.
  • Crash dump partition (cf:3) — Stores the crash dump information.
  • Application partitions (cf:4 and cf:5)—Stores the application software image, system configuration, and ASDM. By default, the FWSM boots off and installs the IOS images on cf:4. You can use cf:5 as a test/backup partition. The contents of this partition (cf:4) is seen with the command ‘dir flash:’
  • Security context partition (cf:6)—64 MB are dedicated to this partition, which stores security context configurations (if desired) and RSA keys in a navigable file system. The contents of this partition is seen with the command ‘dir disk:’

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