dslreports logo
    All Forums Hot Topics Gallery
Search Topic:
share rss forum feed



[HELP] Cisco 831 Router not saving config?

Are there any settings in the router that can prevent writing / saving the startup configuration? All seems to be lost when powering off then on the unit. CDM seems to write to it and all settings seem to be active when saving the config. Also no errors when saving the config in CDM - any one have any ideas? I'll post IOS versions if required but I think this is a general question.


I Need A Nap

Hatboro, PA
Does CDM mean SDM? Or are you using CRWS?

If you are using SDM (CDM), there is a save button at the top, that will write/save the bootup config to flash.

SDM only writes or updates the config that is written in memory, not the bootup config on the flash. That's ware the button comes in.

As for CRWS, I have never used it. But if you search Cisco's website, there is a users guide on it.


Akron, OH
reply to Hazelnut
By default it should save to NVRAM if the config register is set correctly. Run a "show version" and post the output


reply to Hazelnut
Hello -

Thanks for replying.

Yes, I did mean SDM, I have no idea where I got CDM from!

Yes, I am using the "Save" button in SDM and it does appear to save but when the router is powered off then back on, the configuration is lost. Even the passwords are gone and the LAN configurations.

Here is the result from using "Show Version"

Router#show version
Cisco IOS Software, C831 Software (C831-K9O3SY6-M), Version 12.3(7)XR2, RELEASE SOFTWARE (fc1)
Synched to technology version 12.3(7.11)T1
Technical Support: »www.cisco.com/techsupport
Copyright (c) 1986-2004 by Cisco Systems, Inc.
Compiled Fri 25-Jun-04 17:56 by ealyon

ROM: System Bootstrap, Version 12.2(11r)YV5, RELEASE SOFTWARE (fc1)
ROM: Cisco IOS Software, C831 Software (C831-K9O3SY6-M), Version 12.3(7)XR2, RELEASE SOFTWARE (fc1)

Router uptime is 1 minute
System returned to ROM by power-on
System image file is "flash:c831-k9o3sy6-mz.123-7.XR2.bin"

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at:
»www.cisco.com/wwl/export/crypto/ ··· qrg.html
If you require further assistance please contact us by sending email to

Cisco C831 (MPC857DSL) processor (revision 0x500) with 58983K/6553K bytes of memory.
Processor board ID FHK101224P2 (1431813270), with hardware revision 0000
CPU rev number 7
3 Ethernet interfaces
4 FastEthernet interfaces
128K bytes of NVRAM.
12288K bytes of processor board System flash (Read/Write)
2048K bytes of processor board Web flash (Read/Write)

Configuration register is 0x142


Thanks for any advice you can provide.

reminds me of the danse russe
Chandler, AZ
said by Hazelnut :

Configuration register is 0x142
There is the issue. Config register should be 0x2102. Under the terminal configuration mode, use the following command



reply to Hazelnut
Hello all -

I apparently took the 'long way' around to fixing this issue while waiting for any advice from the forum. However, I do want to thank all of you for replying and providing your suggestions / advice.

The 'long way' that I took was:

1 - Getting into the ROM monitor and changing the confreg to 0x2101.

2 - Then I got a configuration summary by entering 'confreg' at the rommon> prompt - I also made changes in this area, particularly the boot characteristics for booting the system.

3 - I restarted the router, entered config t mode and loaded a basic configuration I found on this forum.

4 - I started SDM Express (again) but this time I got the "welcome to your router" splash screen that I haven't seen before - at this point I knew things had gotten a lot better.

So I believe I'm on my way - Thank you all so much! Special thanks to 'elnino' who mentioned the config register and got me thinking and also to 'tubbynet' who responded with the 'direct' fix!