Cisco 1812 reconfig issue

[peter_lengyel]

hi everyone,

one of our customers encountered a strange problem: after a power outage their 1812 router needs to be reconfigured, as if the flash did not hold the running config.

what can cause this? can you pls recommend any diagnostic tools and (or ios commands) i can use to figure out what the problem is? thank you.

peter

[Martin Parry]

Hi

The running config is held in the DRAM of the router. It is only stored in nvram once it has been written / saved to startup config. If the config had never been saved it would be flushed once the box rebooted.

Hope this helps

Martin

[Richard Burts]

Peter

As Martin points out the config is normally stored in NVRAM rather than flash (though there is a configuration option to store the config in flash). But this is a detail and probably your issue is something different.

As Martin points out one possible explanation for this issue is that the config was not saved after being created and was lost at the reboot. In my experience there is another thing that frequently causes this symptom. If the config register is set to 0x2142 then the router boots and ignores the startup config. The symptom looks like the startup config is lost, but if you do show startup it will clearly still be there. Setting the config register is part of password recovery and some other similar maintenance activities and if the config register is not set back to normal at the completion of the maintenance it will produce exactly the symptom that you describe. So please check the value of the config register (it is displayed at the bottom of the show version display).

HTH

Rick

[peter_lengyel]

Hi Rick,

thanks for the tip - I assumed they saved the running config. I'll forward the information about changing the config register, we'll see if that solves the issue.

Thank you, both of you!

Peter