Microsoft KB Archive/272933

= A TCP Session That Ends with a TCP Reset May Not Indicate a Problem =

Article ID: 272933

Article Last Modified on 3/1/2007

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APPLIES TO


 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q272933



SUMMARY
A TCP session that ends with a TCP reset may not indicate a problem. Sometimes TCP resets (RST) indicate a network problem, but there are cases in which a TCP reset is a good thing.



MORE INFORMATION
Because Transmission Control Protocol (TCP) is connection-oriented, most information technology (IT) professionals prefer to see the exchange of FIN ACK packets to perform session teardown. However, in some instances application developers elect to issue a Reset instead to free up resources more quickly for waiting users.

A Reset may also be observed in instances where the destination TCP host is not running the desired service, or if the destination port is unavailable. Both of these methods of session teardown are compliant with RFC 1122:

4.2.2.13 Closing a Connection: RFC-793 Section 3.5

A TCP connection may terminate in two ways:

(1) the normal TCP close sequence using a FIN handshake, and

(2) an &quot;abort&quot; in which one or more RST segments are sent and the connection state is immediately discarded.

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

172983 Explanation of the Three-Way Handshake via TCP/IP

