igb-x.x.x.tag.gz is designed to work with Intel® 82575/6, 82580, I350, and I210/211-based adapters/connections under Linux*. The latest version and earlier versions of this driver are available from SourceForge.
Version 5.0.5k is buggy and will result in serious packet loss. Find which driver version you are using.
# ethtool -i eth1 driver: igb version: 5.0.5-k firmware-version: 1.52, 0x800007ae bus-info: 0000:01:00.1 supports-statistics: yes supports-test: yes supports-eeprom-access: yes supports-register-dump: yes supports-priv-flags: no
If you see a version below 5.2.15 then upgrade immediately.