XenCenter is syncing endless with XenServer

Some days ago I ran into the problem that XenCenter was not connecting to my XenServer correctly. The initial connect seems to be fine, but it got stuck at “synchronizing with …”.

hc_1017-300x182

Further investigation showed that the Server was accesible at TCP/443 and the client was connecting correctly, no hints in XenCenter or XenServer logs. I encountered the same issues with the XAPI Tool xe.exe and powershell commandlets.

I found it even more interesting that I could connect with XenCenter from other clients. The clients causing problems were VMs running inside the XenServer itself, while the other clients – as my local workstation – were connecting without complications. When starting to solve the problem at VM level, I noticed that the problem just starts after XenServer tools were installed.

I had a look in the vNIC driver settings (XenServer tools are updating these drivers at setup) and disabled Large Receive Offload (IPv4) setting. Et Voilà – issue solved!

This issue is related to XenServer Tools 6.0.2.

hc_1016-269x300.png