Network Engineering Stack Exchange is a question and answer site for network engineers. It only takes a minute to sign up.
Sign up to join this community
Does anyone know what this is? Can't read it or delete it, both del and erase nvram do not appear to work on it. I am erasing switches and need to confirm that it does not contain sensitive information.
The name of the file is "persistent-data". It is located at "nvram: persistent-data". It appears when running the latest IOS release for the Cisco 2821 as well as IOS XE.
Will edit post to show output and the additional models of switch I have spotted it on soon.
The router’s NVRAM used to contain the startup configuration file only, but this is no longer strictly the case. Recent IOS releases also use the same NVRAM space to store information such as private keys for SSH or IPSec (private-config), and interface numbers for SNMP (ifIndex-table).
Router1#dir nvram:
Directory of nvram:/
20 -rw- 5068 <no date> startup-config
21 ---- 2302 <no date> private-config
1 ---- 0 <no date> persistent-data
2 -rw- 133 <no date> ifIndex-table
You cannot delete nor read these two files as they strictly belong to the IOS system on your switch or router. Those files do not contain anything sensitive. It is strictly system information that has no relation to any configuration.
Update: OK so i've been searching all over for this and i found this thread:
There's an error generating the following message:
%PRST_IFS-3-GENERAL: persistent media IFS general error: Open Read - can't open nvram:persistent-data errno is 16
Searching for this lead me to believe that the Cisco IOS File System (IFS) saves some persistent date (variables) about the Cisco image in the NVRAM. This data is used upon booting the switch or router.
I wipe clients' sensitive information off of switches for a living. The primary types of switches we work on are the Cisco Catalysts, mainly the 4948 series. Model: WS-C4948E. There are different version numbers, and varied model numbers, but for the most part there a minor differences. You can write the list of commands by entering "help" or "?". You can also see how to complete certain commands by writing a command, such as "write", and then add a "?". For example, entering "erase ?" will write out a list of commands to complete the "erase" command. After entering the command+?, any results that you see show "cr"(with < and > on either side) indicates that you can hit enter with the typed command to execute that prompt. The main commands we use for erasing information off of these switches are "write erase" and "erase /all nvram:". You also want to erase any vlan information by issuing the "erase cat4000_flash:" command. As a double check, we write the command "dir /all all", which will list all the files in each file-system. When it comes to the persistent-data located in the nvram:, it is not possible to delete it. The only possible outcome for a sure-fire reset is to format the system, but that results in a total device wipe, erasing everything including boot files. If you went this route, then the only way it can be booted properly is to add the necessary files back on from the Internet. At that point, it is out of our hands. I hope this helps!
