Networking performance between host and guests is very slow

In this scenario the networking performance between host and guests is very slow, while the networking performance to other lan devices is good (both from the guests and the host). This behaviour has been observed when using guests in bridged networking mode and nics with ip hw acceleration.

Most gigabit nics today have features onboard that offloads parts of the ip stack. Disabling one or more of these will normally resolve this issue.

You should only do this if you absolutely need communication between the guests and the host.

On linux hosts, one or more of the following commands will normally solve this issue:
ethtool -K eth0 tx off    
ethtool -K eth0 sg off  
ethtool -K eth0 tso off 

On windows hosts you will need to use the following command:
Netsh int ip set chimney DISABLED