This article was written for a solution on Server 2008 R2 using Dell, but could still be a viable solution for Server 2012.

Situation:

There was noticable general slowness between guest communications as well as guest to host communications. This included file transfer, domain logon, and name resolution problems.

What we checked:

  • NIC Binding Order
  • IP Version 4 preferred over IPv6
  • NIC Drivers
  • BIOS Versions

Here’s a few links that also support the situation:

http://www.petri.co.il/network-issues-with-windows-server-2008-rdp-on-dell-servers.htm

 http://blog.nicholasrogoff.com/2010/09/24/windows-2008-r2-hyper-vguests-vms-have-slow-performance-change-you-adapter-settings/

 1.       Create a backup:

netsh int tcp show global >C:\TCPGLobalParameters.txt

 2.       You should see:

TCP Global Parameters

———————————————-

Receive-Side Scaling State : disabled

Chimney Offload State : disabled

Receive Window Auto-Tuning Level : disabled

Add-On Congestion Control Provider : ctcp

ECN Capability : disabled

RFC 1323 Timestamps : disabled

 3.       Run the following commands:

netsh int ip set global taskoffload=disabled

netsh int tcp set global RSS=disabled

netsh interface tcp set global autotuninglevel=disabled

netsh int tcp set global chimney=disabled

***optional shown by MS tech***

netsh interface ip set global autotuninglevel=disabled

 

 4.       Command to show Results:

netsh int tcp show global

 5.       You should see:

TCP Global Parameters

———————————————-

Receive-Side Scaling State : disabled

Chimney Offload State : disabled

Receive Window Auto-Tuning Level : disabled

Add-On Congestion Control Provider : ctcp

ECN Capability : disabled

RFC 1323 Timestamps : disabled

 6.       Also verify Registry Changes:

 HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

"EnableTCPA"=dword:00000000

"EnableRSS"=dword:00000000

"DisableTaskOffload"=dword:00000001