This bug has been copied from bug #582367 and has been proposed to be backported to 5.5 z-stream (EUS).
in 2.6.18-194.6.1.el5
You should be able to force LRO off for various drivers by adding them to a bridge interface. Detecting if it works will ususaly require you to look in the message log for various informational driver messages about lro being disabled.
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: Large-Receive Offload (LRO) is a performance optimization that enables the kernel to fetch and process, as a unit, more than one received packet from a network device. It was previously not possible to dynamically disable LRO for devices in a forwanding mode. This has been fixed with this update so that the kernel is able to dynamically disable LRO for devices in a forwarding state, or which had had LRO turned on manually.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2010-0504.html