Document Number: OSUP1053
Product: Machines running Integrated Intel Pro 1000 cards
Date: 11-16-2004
Title: Integrated Intel Pro 1000 Adapters Report All Sent Packets With Bad TCP Checksum

Keywords: Bad TCP Checksum, Integrated, Intel Pro 1000

SYMPTOM:
All TCP packets sent from the console or probe station across an integrated Intel Pro 1000 network adapter contain bad TCP checksums. 

REASONS:
Default driver settings for the card are incorrect. You need to update the driver and then disable the “Offload Transmit TCP Checksum” option.

SOLUTIONS:
  1. Upgrade the driver for the integrated Intel Pro 1000 network adapter to the Network Instruments/Intel Pro 1000 adapter driver.
      This driver is located in the: \<Observer installation directory>\Drivers\IntelPro1000 directory

  2. After upgrading the driver, right click on the adapter and go to properties from the Network Connections window in Control Panel.
     Click on the Configure button located on the General tab. Click on the Advanced tab and locate the option for Offload Transmit TCP Checksum.
     Change this setting from On to Off.

  3. Reboot the system.