This article was previously published under Q257949
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After you enable packet filters on the server, connectivity to IP Security (IPSec) clients may be lost.
This behavior occurs because the Tcpip.sys file does not hand the original packets from Network Driver Interface Specification (NDIS) to IPSec, which causes IPSec to recalculate the hash for a packet that is already unencrypted.
To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
To work around this problem, disable packet filters on the server side host.
Microsoft has confirmed that this is a problem in Microsoft Windows 2000.
This problem was first corrected in Windows 2000 Service Pack 1.
Because the fault is internal to the operating system subsystem, a trace or packet capture does not reveal this problem. Traffic seems to flow normally to the end point, and then disappears into the server without acknowledgement.
For additional information about how to install Windows 2000 and Windows 2000 hotfixes at the same time, click the article number below to view the article in the Microsoft Knowledge Base:
249149 Installing Microsoft Windows 2000 and Windows 2000 Hotfixes