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This article describes how to change the default HTTP keep-alive value in Microsoft Internet Explorer.
When Internet Explorer establishes a persistent HTTP connection with a Web server (by using Connection: Keep-Alive headers), Internet Explorer reuses the same TCP/IP socket that was used to receive the initial request until the socket is idle for one minute. After the connection is idle for one minute, Internet Explorer resets the connection. A new TCP/IP socket is used to receive additional requests. You may want to change the HTTP KeepAliveTimeout value in Internet Explorer.
If either the client browser (Internet Explorer) or the Web server has a lower KeepAlive value, it is the limiting factor. For example, if the client has a two-minute timeout, and the Web server has a one-minute timeout, the maximum timeout is one minute. Either the client or the server can be the limiting factor.
By default, Internet Explorer has a
KeepAliveTimeoutvalue of one minute and an additional limiting factor (
ServerInfoTimeout) of two minutes. Either setting can cause Internet Explorer to reset the socket.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/322756/ )How to back up and restore the registry in Windows
You may have to increase the default time-out value for persistent HTTP connections in Internet Explorer if you are using a Web program that must communicate with Internet Explorer over the same TCP/IP socket after one idle minute. To change the default time-out value for persistent HTTP connections in Internet Explorer, add a DWORD value that is named
KeepAliveTimeoutto the following registry key, and then set its value data to the time (in milliseconds) that you want Internet Explorer to wait before resetting an idle connection:
To do this, follow these steps:
KeepAliveTimeoutvalue to less than 60,000 (one minute), you may have problems communicating with Web servers that require persistent HTTP connections. For example, you may receive a "Page cannot be displayed" error message.
If you must have a
KeepAliveTimeoutvalue higher than 120000 (two minutes), you must create an additional registry key and set its value equal to the
KeepAliveTimeoutvalue that you want. The additional registry key is
ServerInfoTimeout. It is a DWORD with a value (in milliseconds) and in the same location as
For example, to use a three-minute
KeepAliveTimeoutvalue, you must create the following registry keys:
By default, HTTP 1.1 is enabled in Internet Explorer except when you establish an HTTP connection through a proxy server. When HTTP 1.1 is enabled, HTTP connections remain open (or persistent) by default until the connection is idle for one minute or until the value that is specified by the
KeepAliveTimeout DWORD value 180000 (in milliseconds)
ServerInfoTimeout DWORD value 180000 (in milliseconds)
KeepAliveTimeoutvalue in the registry is reached. You can modify HTTP 1.1 settings in Internet Explorer by using the Advanced tab in the Internet Options dialog box.