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TCP bad checksum !!

Hello everyone,

For the past week, I have gotten this error in a couple (out of the 80 or so) of access switches.

Should I be concerned? And if I do, how should I proceed?

Thank you,

Carlos T.

2 REPLIES
Cisco Employee

Re: TCP bad checksum !!

The following page should help

http://www.cisco.com/univercd/cc/td/doc/product/core/cis7600/rel_6_2/sys_msg/emsg.htm#1015421

In order to find out which device is doing it, you need to sniff your Management vlan and look at the trace.

Re: TCP bad checksum !!

Hi,

what type of switches?

L2 switches should't care about TCP checksum unless the target is the switch IP address.

So it might be some kind of DOS attack.....

Or it might be some application with a bug in it's code. I've noticed PGP making incorrect IP header checksum in the past.

Regards,

Milan

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