Router Error Message

Unanswered Question

Our Internet Firewall 2600 series router is producing the following error message:

"SYS-2-CHUNKBADMAGIC Bad magic number in chunk header, chunk 0 data 838AC610 chunkmagic 0 chunk_freemagic 82ED1F00"

I have looked up the error message at the CISCO site, see below:

Error Message

%SYS-2-CHUNKBADFREEMAGIC : Bad free magic number in chunk header, chunk [hex] data [hex] chunk_freemagic [hex]

Explanation An inconsistency was detected while the chunk memory pool was being managed. It is likely that this is a software error, but there could be a hardware memory problem.

Recommended Action Copy the message exactly as it appears on the console or in the system log. Research and attempt to resolve the issue using the tools and utilities provided at . With some messages, these tools and utilities will supply clarifying information. Search for resolved software issues using the Bug Toolkit at . If you still require assistance, open a case with the Technical Assistance Center via the Internet at , or contact your Cisco technical support representative and provide the representative with the information you have gathered. Attach the following information to your case in nonzipped, plain-text (.txt) format: the output of the show logging and show tech-support commands and your pertinent troubleshooting logs.Save any crashinfo or crashdump files. If the router has crashed and was not configured to automatically reload, the router will need to be reloaded manually.

I don't have sufficient rights to access the toolkit any advise on a way ahead would be greatly received. Should I be worried it seems to be working OK?


Richard Bailey

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Overall Rating: 5 (1 ratings)
jcorrale Mon, 03/19/2007 - 16:44
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Most probably, you're hitting the following bug:


Externally found severe defect: Resolved (R)

VFR/NAT: tracebacks in ip_vfr_delete_frag_state and ip_vfr_process


Symptoms: The following tracebacks may be generated when VFR handles

fragmented packets:

%SYS-2-CHUNKBADMAGIC: Bad magic number in chunk header, chunk 0 data 6472EE80

chunkmagic 0 chunk_freemagic 6484FA7C

Conditions: This symptom is observed on a Cisco 7200 series that runs Cisco

IOS interim Release 12.3(12.11)T1 and that is configured with a virtual

reassembly. The symptom may also occur on a Cisco 2651XM.

Workaround: Disable the virtual reassembly by entering the no ip

virtual-reassembly command.

This bug has been fixed in 12.3(14)T03. Therefore an upgrade to a more

recent release will fix that issue.

What is the IOS version of your router? Can you provide the "show tech"?



Richard Burts Tue, 03/20/2007 - 18:23
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I had a set of routers (different platform and different IOS version) that reported the same error message. I opened a case with TAC about it. They did not provide a convincing explanation of the cause but they did recommend a code upgrade. I was frustrated to not know more about what caused the error, but I did upgrade the code. The problem went away.

Especially given that 12.4(1a) is pretty old code at this point, my suggestion to you is to upgrade the code to something pretty recent.



jcorrale Tue, 03/20/2007 - 22:20
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Hi Richard,

The current code has the bug I mentioned fixed but it?s actually a very old code, so I strongly agree with Rick that an IOS upgrade will be the best move in this case. You can try 12.4(7)x, 12.4(8)x or 12.4(10)x.




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