TcpTimedWaitDelay

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

TcpTimedWaitDelay

HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

Description

Specifies the time that must elapse before TCP can release a closed connection and reuse its resources. This interval between closure and release is known as the TIME_WAIT state or 2MSL state. During this time, the connection can be reopened at much less cost to the client and server than establishing a new connection.

RFC 793 requires that TCP maintains a closed connection for an interval at least equal to twice the maximum segment lifetime (2MSL) of the network. When a connection is released, its socket pair and TCP control block can be used to support another connection. By default, the maximum segment lifetime is defined to be 120 seconds, and the value of this entry is equal twice that, or 4 minutes. However, you can use this entry to customize the interval.

Reducing the value of this entry allows TCP to release closed connections faster, providing more resources for new connections. However, if the value is too low, then TCP might release connection resources before the connection is complete, requiring the server to use additional resources to reestablish the connection.

Notes

• Normally, TCP does not release closed connections until the value of this entry expires. However, TCP can release connections before this value expires if it is running out of TCP control blocks. The number of TCP control blocks that the system creates is specified by the value of the MaxFreeTcbs entry.

• Windows Server 2003 does not add this entry to the registry. You can add it by using the registry editor Regedit.exe.