IN THIS TASK
Internet Information Server 4.0 and IIS 5.0 support a method to control the maximum size of the request line and header fields that are accepted by the Internet Information Server and IIS World Wide Web service.
The MaxClientRequestBuffer registry entry is used to limit the amount of data that is accepted in the Internet Information Server and IIS request buffer. This data includes all the information from the first byte of the request through the last byte before the body of the request. This includes the method, the URL, additional path information, the query string, the HTTP version, and all headers and characters that delimit all portions of the request.
The default client request buffer size for Internet Information Server 4.0 is 2 megabytes (MB). The default client request buffer for IIS 5.0 is 128 kilobytes (KB). The default client request buffer for IIS 5.0 Service Pack 4 (SP4) is 16 KB. IIS request buffer size may become the limiting factor for Kerberos authentication with large tokens if users are members of many groups. If a user does have a token that is too large for the IIS server, the client will receive the following in the client's Web browser:
NOTE: See the "Troubleshooting" section of this article before you follow these steps.
- Click Start, click Run, type regedt32, and then press ENTER.
- In Registry Editor, locate and click the following key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\w3svc\parameters
- On the Edit menu, point to New, and then click DWORD Value.
- Type MaxClientRequestBuffer over the
New Value #1 entry.
- Double-click the MaxClientRequestBuffer value.
- In the Edit DWORD Value dialog box, click Decimal in the Base area. In the Value data box, type the byte value that you want to allow to be buffered. Click OK.
- Quit Registry Editor.
- Restart the Web Publishing service for the changes to take effect.
The limit that is set by the MaxClientRequestBuffer registry value is not extremely precise. You may need to experiment with different values to get the results you require. This is especially important because this setting can effect ISAPI filters.
Article ID: 310156 - Last Review: Jul 3, 2008 - Revision: 1