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Wireshark-users: Re: [Wireshark-users] malformed packet

From: Sake Blok <sake@xxxxxxxxxx>
Date: Wed, 1 Sep 2010 00:19:14 +0200
On 31 aug 2010, at 22:15, martin wrote:

> This is not specific to Wireshark however I am using wireshark to analyze this conversation.
> I am getting a bad checksum specifically on one packet. This occurs on a home grown application which is tested on other machines. I would appreciate any pointers as to what this may be due to. Cannot think it could be hardware as it happens only on a specific packet generated by the app.


Without telling us which checksum is bad it's really really hard to be able to help you. Does the checksum occur at the physical layer (ethernet FCS for instance)? At the Network layer (IP header checksum error)? At the transport layer (UDP or TCP checksum error)? Or maybe at a specific upper layer protocol that does calculate checksums? So which protocols are involved and on which layer does the error occur?

Where is the capture made? At the sending or the receiving end (related to the packet with bad checksum)? Was the packet dropped or was it processed?

A little capture file showing the packet with bad checksum and sum surrounding packets might help us help you better.

Cheers,


Sake