Solved

Many tcp "Bad Checksum" on linux server. Does that mean LAN card is broken ?

Posted on 2010-09-16
1
761 Views
Last Modified: 2012-05-10
Hi,
 I've made tcpdump on a linux server - fedora 8.
when I open the cap file with wireshark I see a lot of Errors - at the TCP section :
Checksum: 0xa771 [incorrect, should be 0xa5f8 (maybe caused by "TCP checksum offload"?)]

I guess that's not normal. Does it mean that I have to change my LAN card ?
there are no kernel errors in /var/log/messages log

thank you.
0
Comment
Question by:severel
1 Comment
 
LVL 3

Accepted Solution

by:
gremwell earned 500 total points
ID: 33692792
These errors can appear if your system offloads TCP checksum calculation to NIC. You can disable this feature, but it may increase CPU utilization on your system as CPU will have to deal with checksum calculation. http://www.meshwalk.com/?p=34
0

Featured Post

Maximize Your Threat Intelligence Reporting

Reporting is one of the most important and least talked about aspects of a world-class threat intelligence program. Here’s how to do it right.

Join & Write a Comment

Creating an OSPF network that automatically (dynamically) reroutes network traffic over other connections to prevent network downtime.
PRTG Network Monitor lets you monitor your bandwidth usage, so you know who is using up your bandwidth, and what they're using it for.
Here's a very brief overview of the methods PRTG Network Monitor (https://www.paessler.com/prtg) offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…

705 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

20 Experts available now in Live!

Get 1:1 Help Now