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TCP Checksum Offload is not equal to TCP Task Offload. This is an issue that lately I have been answering a lot in the Hyper-V TechNet forum.

TCP Checksum Offload is not equal to TCP Task Offload

Folks find a link that refers to disabling Checksum Offloading or TCP Offload to help with strange networking behavior with an application server (Remote Desktop Services, XenApp, Exchange, SQL, SharePoint, etc.). So they disable “TCP Checksum Offload” using netsh on the Hyper-V Server. The end result is that the problem is not resolved, so they come to the forum. In actuality they did not disable the correct feature. So here is my third attempt to try and straighten this out. In this particular scenario the features (yes, multiple with some NIC drivers) are referred to as TCP Task Offload. There is a really ancient Microsoft KB article that talks about this. I am going to paraphrase it here: Click Start, click Run, type ncpa.cpl, and then click OK.

If you have Server Core the following might help: Information about the TCP Chimney Offload, Receive Side Scaling, and Network Direct Memory Access features in Windows Server 2008. Cet article décrit les fonctionnalités de déchargement TCP Chimney, de mise à l'échelle côté réception (RSS) et d'accès direct à la mémoire réseau (NetDMA) disponibles pour le protocole TCP/IP sous Windows Server 2008.

Information about the TCP Chimney Offload, Receive Side Scaling, and Network Direct Memory Access features in Windows Server 2008

Strange logon drivemapping problem after updgrade to DC 2008 R2 (Network Steve Forum) Troubleshooting the intermittent slow logon or slow startup - AD Troubleshooting. Update: See also the following articles for up-to-date information on how to fix slow logon issues in Windows systems: Sometimes the following issue turns up as a support case with Microsoft Support: Every now and then, we have a slow logon to several of our workstations.

Troubleshooting the intermittent slow logon or slow startup - AD Troubleshooting

We can't see a pattern in which users or computers are involved and we can't reproduce the issue consistently. Most of the time everything works fine and the users log on without problems. When the issue *does* occur; the machine typically hangs for a long time during the ‘Applying Computer Group Policy’ or ‘Applying User Group Policy’ or ’Running Startup Scripts’ stages. This is usually a difficult and time-consuming problem to troubleshoot. Windows XP and Windows Vista have a feature called Fast Logon Optimization, which means that the user is allowed to enter their credentials before the machine itself is fully ready to service logons. Once you have a reproducable scenario, you can follow up with things like: Using Registry Values to Enable and Disable Task Offloading. Task offload keywords belong to one of two groups: granular keywords or grouped keywords.

Using Registry Values to Enable and Disable Task Offloading

Granular keywords provide keywords per offload capability--Transport Layer differentiation, IP protocol differentiation. Grouped keywords provide combined keywords capability at the transport layer. The granular keywords are defined as follows: *IPChecksumOffloadIPv4 Describes whether the device enabled or disabled the calculation of IPv4 checksums. *TCPChecksumOffloadIPv4 Describes whether the device enabled or disabled the calculation of TCP Checksum over IPv4 packets.

*TCPChecksumOffloadIPv6 Describes whether the device enabled or disabled the calculation of TCP checksum over IPv6 packets. The Command-Line in Windows XP: Netsh, the Network Services Shell. A suite of command line networking tools called Netsh that comes with its own shell or interface is contained in a number of Windows operating systems and is discussed here.

The Command-Line in Windows XP: Netsh, the Network Services Shell

Introduction to Netsh As more and more home users set up networks, they are finding themselves to be de facto system administrators. Home networks are very nice but they require a certain amount of care and feeding. Fortunately, Windows XP comes with a large assortment of command-line tools that can help maintain your network. Although many are specialized and of interest only to administrators of large corporate setups, some tools can be quite helpful to the home user as well.

Many may find that the basic tools like ping, ipconfig, and netstat, which are discussed on another page, are all that they care to deal with but the more adventurous can take advantage of a complete suite of powerful tools called Netsh. The Network Services shell is opened by entering netsh into a regular command prompt. Back to top.