Avoiding TCP/IP Port Exhaustion

When a client initiates a TCP/IP socket connection to a server, the client typically connects to a specific port on the server and requests that the server respond to the client over an ephemeral, or short lived, TCP or UDP port. On Windows Server 2003 and Windows XP the default range of ephemeral ports used by client applications is from 1025 through 5000. Under certain conditions it is possible that the available ports in the default range will be exhausted.

Increase the upper range of ephemeral ports that are dynamically allocated to client TCP/IP socket connections.

Start Registry Editor.

Browse to, and then click the following key in the registry:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

On the Edit menu, click New, DWORD Value, and then add the following registry value to increase the number of ephemeral ports that can by dynamically allocated to clients:

Value name:MaxUserPort

Value data



Close Registry Editor.

Note
You must restart your computer for this change to take effect.

Note

Increasing the range of ephemeral ports used for client TCP/IP connections consumes Windows kernel memory. Do not increase the upper limit for this setting to a value higher than is required to accommodate client application socket connections so as to minimize unnecessary consumption of Windows kernel memory.
Reduce the client TCP/IP socket connection timeout value from the default value of 240 seconds

Start Registry Editor.

Browse to, and then click the following key in the registry:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

On the Edit menu, click New, DWORD Value, and then add the following registry value to reduce the length of time that a connection stays in the TIME_WAIT state when the connection is being closed. While a connection is in the TIME_WAIT state, the socket pair cannot be reused:

Value name

TcpTimedWaitDelay

Value data



Close Registry Editor.

Note:

You must restart your computer for this change to take effect.