This issue occurs when the host settings have been changed in 5.5 or 6.0 which prevents a Network Interface Card with an RX ring size 2 buffer size > 2048 from communicating. By default the value of the RX ring size 2 is 4096.
This is a known issue affecting ESXi 5.5 Update 3 and 6.0.
For ESXi 5.5 Update 3
For ESXi 6.0
To work around this issue, change the Rx Ring #2 to 2048 prior to migrating the virtual machine back to the 5.5 hosts.
Steps to change the Rx Ring size would be mentioned below:
- Log in to the guest OS.
- Open Device Manager.
- Click on Network adapters.
- Right-click the network adapter for which you want to change the settings, and then click properties.
- Select Advanced tab.
- Select Rx Ring #2 size from the scroll bar.
- Set the value to 2048 manually.