[c-nsp] IP Header Checksum Errors

Ivan cisco-nsp at itpro.co.nz
Mon Feb 14 04:42:57 EST 2011


Hi,

I have a 6509 running 12.2(18)SXF4.  I find a lot of the following errors
in the logs

%MLS_STAT-SP-4-IP_CSUM_ERR: IP checksum errors
%EARL_L3_ASIC-SP-3-INTR_WARN: EARL L3 ASIC: Non-fatal interrupt Packet
Parser block interrupt

>From what I read, these are informational
(http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801b42bf.shtml#EARL)

While as per the above I could disable the informational message I could
also try to locate and fix the problem.  I don't imagine SPAN will
actually SPAN packets with IP header checksum errors and even if it does
it seems it may be hard to get a sniffer that has an OS that will not also
discard the packets.  I was wondering if anyone had any ideas or
experience with this.

Also using ELAM
(http://cisco.cluepon.net/index.php/Using_capture_buffer_with_ELAM or
https://supportforums.cisco.com/message/3006679?tstart=-1) would be good. 
I am not sure if the filter can be set to packets with IP header checksum
errors either....

Cheers

Ivan



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