1. Attach a terminal or PC with terminal emulation to the console port of the router. Use the following terminal settings:
9600 baud rate
8 data bits
1 stop bit
No flow control
The required console cable specifications are described in the Cabling Guide for RJ-45 Console and AUX Ports (Cisco’s 1000 series, 2500 series, and AS5100).
2. If you still have access to the router, type show version and record the setting of the configuration register; it is usually 0x2102 or 0x102. Click here to see the output of a show version command.
3. If you don’t have access to the router (because of a lost login or tacacs password), you can safely consider that your configuration register is set to 0x2102.
4. Using the power switch, turn off the router and then turn it back on.
Important: To simulate step 4 on a Cisco 6400, pull out and then replace the Node Route Processor (NRP) or Node Switch Processor (NSP) card.
Important: To simulate step 4 on a Cisco 6×00 using NI-2, pull out and then replace the NI-2 card.
5. Press Break on the terminal keyboard within 60 seconds of the power-up to put the router into ROMMON.
If the break sequence doesn’t work, see Possible Key Combinations for Break Sequence During Password Recovery for other key combinations.
6. Type confreg 0x2142 at the rommon 1> prompt to boot from Flash without loading the configuration.
7. Type reset at the rommon 2> prompt.
The router reboots but ignores its saved configuration.
8. Type no after each setup question or press Ctrl-C to skip the initial setup procedure.
9. Type enable at the Router> prompt.
You’ll be in enable mode and see the Router# prompt.
10. Important: Type configure memory or copy startup-config running-config to copy the nonvolatile RAM (NVRAM) into memory. Do not type configure terminal.
11. Type write terminal or show running-config.
The show running-config and write terminal commands show the configuration of the router. In this configuration you see under all the interfaces the shutdown command, which means all interfaces are currently shutdown. Also, you can see the passwords (enable password, enable secret, vty, console passwords, and so on) either in encrypted or unencrypted format. The unencrypted passwords can be re-used, the encrypted ones will have to be changed with a new one.
12. Type configure terminal and make the changes.
The prompt is now hostname(config)#.
13. Type enable secret
to change the enable secret password, for example.
14. Issue the no shutdown command on every interface that is used. If you issue a show ip interface brief command, every interface that you want to use should be “up up”.
15. Type config-register 0x2102, or the value you recorded in step 2.
16. Press Ctrl-z or end to leave the configuration mode.
The prompt is now hostname#.
17. Type write memory or copy running-config startup-config to commit the changes.