HTTP Error 403.6

SYMPTOMS
When connecting to Internet Information Services using a Web browser, you may receive the following error message:

HTTP 403.6 - Forbidden: IP address rejected
CAUSE
Each client has a unique IP address. If the server defines a list of IP addresses that are not allowed to access the site and the IP address you are using is on this list, you will receive the error message.

This is a feature that grants or denies specific users access to a Web site, directory, or file.
RESOLUTION
To resolve this problem:
Using the Internet Service Manager (Microsoft Management Console), open the Internet Information Server (IIS) snap-in and select the Web site reporting the 403.6 error. Right-click the Web site, virtual directory, or file where the error is occurring. Click Properties to display the property sheet for that item.
Select the appropriate Directory Security or File Security property page. Under IP Address and Domain Name Restrictions, click Edit.
In the IP Address and Domain Name Restrictions dialog box, if the Denied Access option is selected, then add the IP address, network ID, or domain of the computer that requires access to the exceptions list.

In the IP Address and Domain Name Restrictions dialog box, if the Granted Access option is selected, then remove the IP address, network ID, or domain of the computer that requires access to the exceptions list.
IMPORTANT:
When you set security properties for a specific Web site, you automatically set the same security properties for directories and files belonging to that site, unless the security properties of the individual directories and files have been previously set.
Your Web server will prompt you for permission to reset the properties of individual directories and files when you attempt to set security properties for your Web site. If you choose to reset these properties, your previous security settings will be replaced by the new settings. The same condition applies when you set security properties for a directory containing subdirectories or files with previously set security properties.

Og læs selv her : http://support.microsoft.com/default.aspx?scid=KB;EN-US;248043

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