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Cisco C2951 Router Reboots

The Cisco 2951 Router I am managing lately reboots almost daily. It was connected to a UPS, I thought it was UPS problem so I connected it directly to a wall outlet. But still it reboots. Please see attached files for the results of the show version, show environment and show logging. Hope you could help me.


Overview of Show Version:

Router uptime is 47 minutes
System returned to ROM by address error at PC 0x6D07740, address 0xD0D0D11 at 02:13:58 UTC Sat Jan 4 2020
System image file is "flash0:c2951-universalk9-mz.SPA.152-4.M4.bin"
Last reload type: Normal Reload
Last reload reason: address error at PC 0x6D07740, address 0xD0D0D11

14 Replies 14


The reboot is result this error;

Last reload reason:address error at PC 0x6D07740, address 0xD0D0D11

The router is encountering a problem which could be a likely hardware
failure. I would suggest logging a ticket with TAC if the device has a
valid support contract.


Hi Sir,


Unfortunately, we no longer has support. But when show environment is executed, it shows everything is normal


Router#SHOW environment
Internal Power Supply Type: AC
Internal Power Supply 12V Output Status: Normal

External Redundant Power Supply is absent or powered off

Fan 1 OK, Low speed setting
Fan 2 OK, Low speed setting
Fan 3 OK, Low speed setting
Fan 4 OK, Low speed setting

Intake Left temperature: 23 Celsius, Normal
Intake Right temperature: 19 Celsius, Normal
Exhaust Left temperature: 32 Celsius, Normal
Exhaust Right temperature: 24 Celsius, Normal
CPU temperature: 52 Celsius, Normal
Power Supply Unit temperature: 26 Celsius, Normal

Battery OK (checked at power up)

Motherboard Components Power consumption = 64.2 W
Total System Power consumption is: 64.2 W

Environmental information last updated 00:00:20 ago



 - Another possible  cause can be a software bug , consider upgrading to more recent and or advisory release if available , applicable, and or feasible.


-- ' 'Good body every evening' ' this sentence was once spotted on a logo at the entrance of a Weight Watchers Club !

Hi Sir,


The IOS has not been upgraded/updated since it was first installed 2015 as far as i know. Is there a feature of the Cisco IOS to automatically update its IOS? 

Thank you.


                           - Not on this platform, you have to update manually - which is strongly advised.


-- ' 'Good body every evening' ' this sentence was once spotted on a logo at the entrance of a Weight Watchers Club !

#dir nvram 

see if IFINDEX file is there or not 


if there and it "0"
please do copy run and 

do dir nvram again to see if the size is high than zero.

Hi Sir,


Below is the result when issuing the said command on the router


Router#dir nvram
%Error opening flash0:/nvram (File not found)

#dir nvram:
: meaning this is folder not file, check this.
I think you face issue with interface index.



I'd also say, try the recommended IOS release (Release 15.7.3M7 MD), which is a maintenance deployment release that provides bug fixes...

Hi Sir,


Is it possible that a bug just showed up recently since this is the first time we encounter this problem after installing/running this router since 2015. and as far as i know, the IOS hasn't been changed/upgraded.


Thank you.



bugs can show up at random times. You either have a hardware failure, or are encountering a software bug. You can exclude the latter by loading the recommended IOS, if that doesn't help, the most likely culprit is a hardware issue.

It is difficult to determine what is causing this problem. The show logging output that was in the original post shows only a minute or two after reboot. And that does not help find the issue. I wonder if a show log after the router had been running for a while might show something helpful. In particular I am wondering if there are any messages in the log indicating traceback? If so this would pretty conclusively point to a software problem.


I agree with @Georg Pauwen that software bugs can show up at any time. But I would think that if the router ran for 5 years with no issue and now is rebooting on an almost daily basis that it is likely not a software bug.


Ultimately I am not sure that it is important to find out what is causing this issue. If it turns out to be a software issue then they need support from TAC. If it turns out to be a hardware issue then they need support from TAC. But the original poster has clearly said that they no longer have support for this router. 


I don't think that there is an attractive solution for the original poster. Updating software is not possible without a support contract. Repairing hardware is not possible without a support contract. It looks to me like the original poster is going to need to replace this router.



Hi Sir,


Its kind a weird when i changed created a new username and deleted the existing one, the rebooting stopped.


Thanks for the update. Glad to know that the rebooting has stopped. And very surprised that replacing the user name and password was the fix. But if the router is now running reliably then that is a very good thing.


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