After you install Windows Server 2003 Service Pack 2 (SP2)
or Windows Server 2003 Scalable Networking Pack (SNP) on a computer that has a
TCP/IP Offload-enabled network adapter, you may experience many network-related
problems.
When you try to connect to the server by using a VPN
connection, you receive the following error message:
Error 800: Unable to establish connection.
You cannot create a Remote Desktop Protocol (RDP)
connection to the server.
You cannot connect to shares on the server from a computer
on the local area network.
You cannot join a client computer to the domain.
You cannot connect to the Exchange server from a computer
that is running Microsoft Outlook.
Inactive Outlook connections to the Exchange server may not
be cleaned up.
You experience slow network performance.
You may experience slow network performance when you
communicate with a Windows Vista-based computer.
You cannot create an outgoing FTP connection from the
server.
The Dynamic Host Configuration Protocol (DHCP) server
service crashes.
You experience slow performance when you log on to the
domain.
Network Address Translation (NAT) clients that are located
behind Windows Small Business Server 2003 or Internet Security and Acceleration
(ISA) Server experience intermittent connection failures.
You experience intermittent RPC communications
failures.
The server crashes.
The server runs low on nonpaged pool memory
Note SNP features are currently not supported on Itanium-based
systems.
This update turns off default SNP features. After you install this hotfix, you can manually re-enable these features by changing registry values. The following
files are available for download from the Microsoft Download
Center:
For more information about how to
download Microsoft support files, click the following article number to view
the article in the Microsoft Knowledge Base:
How to obtain Microsoft support files from online services
Microsoft scanned this file for viruses. Microsoft used the most
current virus-detection software that was available on the date that the file
was posted. The file is stored on security-enhanced servers that help prevent
any unauthorized changes to the file.
Prerequisites
You must have Windows Server 2003 Service Pack 2 installed.
Restart requirement
You must restart the computer after you apply this update.
Hotfix replacement information
This update does not replace any other previously released
updates.
To see whether an updated network adapter driver is available, contact the network adapter manufacturer or the original equipment manager (OEM) for the computer. The driver must meet Network Driver Interface Specification (NDIS) 5.2 or a later version of this specification.
For information about how to contact computer program manufacturers, go to the following Microsoft website:
To have us do this for you, go to the "Fix it for me" section. If you would rather do this yourself, go to the "Let me fix it myself" section.
Fix it for me
To disable RSS and TCP Offload in the registry automatically, click the Fix this problem link. Then click Run in the File Download dialog box, and follow the steps in this wizard.
Note this wizard may be in English only. However, the automatic fix also works for other language versions of Windows.
Note If you are not on the computer that has the problem, you can save the automatic fix to a flash drive or to a CD. Then you can run the automatic fix on the computer that has the problem.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
Right-click EnableTCPChimney, and then
click Modify.
In the Value data box, type
0, and then click OK.
Right-click EnableRSS, and then click
Modify.
In the Value data box, type
0, and then click OK.
Right-click EnableTCPA, and then click
Modify.
In the Value data box, type
0, and then click OK.
Exit Registry Editor, and then restart the
computer.
If you set the value of the EnableTCPChimney registry entry to
1, the TCP Chimney functionality is enabled. Similarly, if you set the values
of the EnableRSS and EnableTCPA registry entries to 1, the RSS functionality
and the TCPA functionality are enabled.
Check whether the problem is fixed. If it is fixed, you are finished with this article. If it is not fixed, you can contact support. To do this, go to the Microsoft Support for small business
These issues occur because of several problems with the Windows Server 2003 SNP features that are enabled in Windows Server 2003 Service Pack 2. These features include Receive Side Scaling (RSS) and TCP/IP
Offloading. Specifically, these problems include the following:
RSS is incompatible with NAT or with Network Load Balancing (NLB).
TCP/IP Offload has a problem with the Window Scaling feature. This problem typically occurs when you communicate with a Windows Vista-based computer. Windows Vista uses the Window Scaling feature.
Some TCP/IP Offload-enabled network adapters do not send TCP keep-alive messages but Exchange servers use TCP keep-alive messages to clean up inactive client sessions.
The TCP/IP Offload-enabled network adapter may consume lots of nonpaged pool memory. This may cause other problems in the operating system.
In some cases, the TCP/IP Offload-enabled network adapter may request large blocks of contiguous memory. This makes the computer crash when it tries to free the memory.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
The Microsoft Windows Server 2003 Scalable Networking Pack release
In rare cases, this hotfix does not work. For example, when you use network adapter teaming software on the computer, the changes to TCP Chimney and RSS settings are not picked up by the network adapter teaming software. This causes a loss of network connectivity. After you apply this hotfix, you must verify the properties of the network adapter team to make sure that the TCP Chimney or TOE and RSS settings have also been disabled. If the hotfix cannot disable the TCP Chimney or TOE and RSS feature, you can manually disable RSS and TCP Chimney Offload by using one of the methods that is mentioned in the Workaround section.
The third-party products that this
article discusses are manufactured by companies that are independent of
Microsoft. Microsoft makes no warranty, implied or otherwise, about the
performance or reliability of these
products.
Microsoft provides third-party contact information to help you
find technical support. This contact information may change without notice.
Microsoft does not guarantee the accuracy of this third-party contact
information.
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