The Internet Information Server (IIS) log-file format contains a parameter
for processing time. This field is the total amount of processing time
that is spent on the server for a particular DLL. This internal timer
starts on Packet 1 and ends on the last Acknowledgement received from the
client indicating that that the processing has been completed on the
server. However, the logged time is not correct if KeepAlive is enabled
for the connection between the IIS computer and the Internet browser.
The counter that measures time is not reset for KeepAlive connections.
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the
Microsoft Knowledge Base:
How to Obtain the Latest Windows NT 4.0 Service Pack
Microsoft has confirmed this to be a problem in Internet Information
Server version 4.0. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.