Why are my gigabit network cards not working after I upgraded my Red Hat Enterprise Linux 4.5 kernel?

This issue is only seen with users who upgrade the kernel to 2.6.9-67* without also upgrading their ethtool package.

Generally there are no issues when upgrading just the kernel to the latest release and leaving other packages untouched. In this case new network drivers for many gigabit cards will not fully function unless the ethtool package is also upgraded. The issues can be fail...