BalanceNG Release 4.071 and higher switches the offloading optimisations off automatically (if ethtool is installed). If you are running an earlier release you would need to perform the steps as explained. Better, yet, just upgrade to the latest release.
On Linux operating systems any offloading optimisation needs to be disabled, the following command disables this for eth0, for example:
ethtool --offload eth0 rx off tx off gso off gro off lro off tso off
In order to make this permanent (reboot-safe), this instruction needs to be placed in a suitable ‘pre-up’ script for any interface being accessed by BalanceNG.