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Beginner

how to reset cisco router 1841 password

Hi

Hava cisco router 1841 forgot user name and password and need to reset it to its factory setting pls help

tried boot while holding ctrl and break get into rommon1>

rommon1>confreg 0*2142

rommon1>reset

still shows rommon 3>

pls help,it ask user name and password and cant remember both

thx

J

2 ACCEPTED SOLUTIONS

Accepted Solutions
Highlighted
Cisco Employee

You need to boot the router after that.

Type boot from the rommon if you have set the boot variable correctly

View solution in original post

Highlighted

Hi Joseph,

Please execute the below command on the rommon prompt again,

rommon>confreg 0x2142 (not confreg 0*2142)

rommon>reset

Please see the regular process to reset the password on 1841 Router below,

  • Connect the console cable to Router 1841
  • Use the power switch in order to turn off the router, and then turn the router back on
  • Press Break on the terminal keyboard within 60 seconds of power up in order to put the router into ROMMON
  • Type confreg 0x2142 at the rommon 1> prompt in order to boot from Flash

          This step bypasses the startup configuration where the passwords are stored

  • Type reset at the rommon 2> prompt.

          The router reboots, but ignores the saved configuration.

  • Type no after each setup question, or press Ctrl-C in order to skip the initial setup procedure.
  • Type enable at the Router> prompt.
  • You are in enable mode and should see the Router# prompt.
  • Type copy startup-config running-config in order to copy the nonvolatile RAM (NVRAM) into memory.

Important:

Do not type copy running-config startup-config or write. These commands erase your startup           configuration.

  • Type configure terminal
  • Type #enable secret <password> in order to change the enable secret password.
  • Type config-register #config-register 0x2102
  • Type write memory or #copy running-config startup-config in order to commit the changes

Refer:

http://www.cisco.com/en/US/products/hw/routers/ps221/products_password_recovery09186a0080094773.shtml

If you couldnt boot the device after execute the below commands,

rommon>confreg 0x2142

rommon>reset

As Ivan suggested, please try to boot the image from flash or bootflash where you stored the actual IOS image

rommon>boot (Boot the first image in flash memory)

rommon>boot flash:[filename] (Boot the first image or a specified image in flash memory)

rommon>boot <filename> tftpserver (Boot the specified image over the network from the specified TFTP server (hostname or IP address)

example: rommon>boot <image name> 172.16.30.40

If this doesnt work, you can recover the System Image (tftpdnld)

Note: Use the tftpdnld command only for disaster recovery because it can erase all existing data in flash memory before it downloads a new software image to the router.

Before you can enter the tftpdnld command, you must set the ROM monitor environment variables.

Prerequisites

Connect the TFTP server to a fixed network port on your router.

rommon 16 > IP_ADDRESS=171.68.171.0

rommon 17 > IP_SUBNET_MASK=255.255.254.0

rommon 18 > DEFAULT_GATEWAY=171.68.170.3

rommon 19 > TFTP_SERVER=171.69.1.129

rommon 20 > TFTP_FILE=c2600-i-mz.120-7.T.bin

rommon 21 > tftpdnld

After the tftpdnld procedure is complete, the router goes back to a ROMmon prompt.

Issue the confreg 0x2102 command and reset. If the confreg 0x2102 command is not issued, the router boots to ROMmon mode after the reset

rommon1>confreg 0x2102

rommon2>reset

Refer:

http://www.cisco.com/en/US/docs/routers/access/1800/1841/software/configuration/guide/b_rommon.html

https://supportforums.cisco.com/docs/DOC-2340

Regards,

Aru

Regards, Aru *** Please rate if the post useful ***

View solution in original post

18 REPLIES 18
Highlighted
Cisco Employee

You need to boot the router after that.

Type boot from the rommon if you have set the boot variable correctly

View solution in original post

Highlighted

how to boot that correctly pls?

Highlighted

sorry just ticked on correct answer wrongly?

still need ans

Highlighted

Hi,

Since the router is in ROMMON after reset, it means the autoboot failed. Likely router cannot find the image.

Do you know where it is located? Use "dev" command in ROMMON mode to see file systems, then "dir ..." to list the files in each of them and boot with correct image manually using "boot ...".

     dev   

     dir :

     boot :

PS: please capture console logs from the terminal when working this steps. In case of some issues it will help to find the problem.

Kind Regards,
Ivan Shirshin

**Please grade this post if you find it useful.

Kind Regards,
Ivan
Highlighted

Hi Joseph,

As Ivan said, it failed to auto boot after you gave reset from rommon prompt. I would like to confirm you one more thing, did you try to execute * or x

I mean, 0*2142 or 0x2142

Regards,

Aru

Regards, Aru *** Please rate if the post useful ***
Highlighted

0*2142

Highlighted

Hi Joseph,

Please execute the below command on the rommon prompt again,

rommon>confreg 0x2142 (not confreg 0*2142)

rommon>reset

Please see the regular process to reset the password on 1841 Router below,

  • Connect the console cable to Router 1841
  • Use the power switch in order to turn off the router, and then turn the router back on
  • Press Break on the terminal keyboard within 60 seconds of power up in order to put the router into ROMMON
  • Type confreg 0x2142 at the rommon 1> prompt in order to boot from Flash

          This step bypasses the startup configuration where the passwords are stored

  • Type reset at the rommon 2> prompt.

          The router reboots, but ignores the saved configuration.

  • Type no after each setup question, or press Ctrl-C in order to skip the initial setup procedure.
  • Type enable at the Router> prompt.
  • You are in enable mode and should see the Router# prompt.
  • Type copy startup-config running-config in order to copy the nonvolatile RAM (NVRAM) into memory.

Important:

Do not type copy running-config startup-config or write. These commands erase your startup           configuration.

  • Type configure terminal
  • Type #enable secret <password> in order to change the enable secret password.
  • Type config-register #config-register 0x2102
  • Type write memory or #copy running-config startup-config in order to commit the changes

Refer:

http://www.cisco.com/en/US/products/hw/routers/ps221/products_password_recovery09186a0080094773.shtml

If you couldnt boot the device after execute the below commands,

rommon>confreg 0x2142

rommon>reset

As Ivan suggested, please try to boot the image from flash or bootflash where you stored the actual IOS image

rommon>boot (Boot the first image in flash memory)

rommon>boot flash:[filename] (Boot the first image or a specified image in flash memory)

rommon>boot <filename> tftpserver (Boot the specified image over the network from the specified TFTP server (hostname or IP address)

example: rommon>boot <image name> 172.16.30.40

If this doesnt work, you can recover the System Image (tftpdnld)

Note: Use the tftpdnld command only for disaster recovery because it can erase all existing data in flash memory before it downloads a new software image to the router.

Before you can enter the tftpdnld command, you must set the ROM monitor environment variables.

Prerequisites

Connect the TFTP server to a fixed network port on your router.

rommon 16 > IP_ADDRESS=171.68.171.0

rommon 17 > IP_SUBNET_MASK=255.255.254.0

rommon 18 > DEFAULT_GATEWAY=171.68.170.3

rommon 19 > TFTP_SERVER=171.69.1.129

rommon 20 > TFTP_FILE=c2600-i-mz.120-7.T.bin

rommon 21 > tftpdnld

After the tftpdnld procedure is complete, the router goes back to a ROMmon prompt.

Issue the confreg 0x2102 command and reset. If the confreg 0x2102 command is not issued, the router boots to ROMmon mode after the reset

rommon1>confreg 0x2102

rommon2>reset

Refer:

http://www.cisco.com/en/US/docs/routers/access/1800/1841/software/configuration/guide/b_rommon.html

https://supportforums.cisco.com/docs/DOC-2340

Regards,

Aru

Regards, Aru *** Please rate if the post useful ***

View solution in original post

Highlighted

After the following command

 

Type config-register #config-register 0x2102

you need to press ctl-z to signify the end of the commands before you can write this back to memory using

Type write memory or #copy running-config startup-config in order to commit the changes

Highlighted

Hi, i have an 1812 rooter, and i want to reset him but i don't have password and i can't reset him because the rommon mode was blocked, how can i reset rooter without rommon mod ?

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You can try this section, if that doesnt work not sure

Recovering a Device from the No Service Password-Recovery Feature

To recover a device once the No Service Password-Recovery feature has been enabled, use the telnet client only (SSH is not supported). This telnet client is capable of breaking out of the current session by pressing “Ctrl+]” keys together to arrive at the “telnet>” prompt. At this prompt, you can send multiple strings of “send break” during the “#####” boot up window followed by the “Self decompressing the image :” message. You must send five to seven strings of “send break” during the break out session to arrive at the “Do you want to reset the router to factory default configuration and proceed [y/n] ?” prompt. Answer “yes” for the device to boot with the factory default configuration. If Putty client is used for the telnet session, use the break command from the drop down menu. For SecureCRT client with telnet session, press the “Ctrl +break” keys on the full keyboard. The router will not go into ROMmon mode during this recovering process.

If you do not confirm the Break key action, the router boots normally with the No Service Password-Recovery feature enabled.

Examples
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/sec_usr_cfg/configuration/15-sy/sec-usr-cfg-15-sy-book/sec-no-svc-pw-recvry.html
Highlighted

Hi Aru,

this is what happened,what next?

rommon 2 > dev

Devices in device table:

        id  name

    flash:  external compact flash

bootflash:  boot flash

    eprom:  eprom

j

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get the following output

dir bootflash:

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rommon 1 > dir bootflash:

monitor: command "dir" not found

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Please get the following output

rommon 1 > ?

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