When you transfer a large file by HTTP it will disconnect and give you this error:
Disconnecting: Corrupted MAC on input.
This can also happen on SSH, FTP or other protocols as this is a bug with the kernel driver for the network.
Turn off "offload check summing" with the following command:
ethtool -K eth0 rx off tx off
Depending on the Ethernet driver in use this may not work as some drivers do not support turning off this feature.