Cisco

Devices

• Cisco Switch
• Cisco Router
• Cisco AP

General

write erase
delete vlan.dat

Erasing all in NVRAM, also files, that cannot be erased by delete command (Permision denied)

erase /all nvram:

Show all memories and their content

dir /all all

First enables Gratutious ARP from host to router, second in PPP connection. It is recommended to disable the second.

ip arp gratuitous
ip gratuitous-arp

Password recovery

2960, 3560, 3750

1. unplug power cable
2. while holding mode button reconnect power cable
3. "sys" LED starts to blink
4. after approx 15 sec. release button, LED will disappear or will be solid (this is the time to release)
5. "flash_init"
6. "load_helper" - not everytime is supported
7. dir flash:
8. rename flash:config.text flash:cfg.text
9. "boot"

ASA

1. unplug power cable
2. during booting press ESC to get to rommon
3. "confreg" - save register number display afterwards
4. After asking "Do you want to change the configuration?" type "Yes"
5. When asking "ignore system configuration?" or "disable system configuration?" type "Yes"
6. All other questing to default "no"
7. "boot"
8. "copy startup running"
9. "write erase"
10. "no config-register <saved_register_number>" usually it is 0x1 and you do not have to specify number
https://community.cisco.com/t5/security-documents/asa-password-recovery/ta-p/3126046
https://www.petenetlive.com/KB/Article/0000572

OTHER

1. unplug power cable
2. during booting check screen, sometimes it show how to enter rommon
3. usually enter it pressing ESC or Ctrl+Break / Fn + Break
4. "confreg 0x2142"
5. "reset"
6. after reboot
7. type "configure memory" or "copy startup-config running-config"