Using this class, it is possible to ensure that callers are from a specific Web site. Site identity is only defined for code from URLs with the protocols of HTTP, HTTPS, and FTP. A site is the string between the "//" after the protocol of a URL and the following "/", if present, for example, www.fourthcoffee.com in the URL http://www.fourthcoffee.com/process/grind.htm. This excludes port numbers. If a given URL is http://www.fourthcoffee.com:8000/, the site is www.fourthcoffee.com, not www.fourthcoffee.com:8000.
Sites can be matched exactly, or by a wildcard ("*") prefix at the dot delimiter. For example, the site name string *.fourthcoffee.com matches fourthcoffee.com as well as www.fourthcoffee.com. Without a wildcard, the site name must be a precise match. The site name string * will match any site, but will not match code that has no site evidence.
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In the .NET Framework versions 1.0 and 1.1, demands on the identity permissions are effective, even when the calling assembly is fully trusted. That is, although the calling assembly has full trust, a demand for an identity permission fails if the assembly does not meet the demanded criteria. In the .NET Framework version 2.0, demands for identity permissions are ineffective if the calling assembly has full trust. This assures consistency for all permissions, eliminating the treatment of identity permissions as a special case.
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Caution: |
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SiteIdentityPermission grants permission for all paths to the site, including both the URL and the IP address. To Deny access to a site, you must Deny all possible paths to the site. For example, if www.fourthcoffee.com is located at IP address 192.168.238.241, to Deny access to www.fourthcoffee.com, you must Deny www.fourthcoffee.com, 192.168.238.241 and any other path that you can use to access the site. A better technique to deal with multiple paths is to use a combination of PermitOnly and Deny. For more information on this subject and the use of PermitOnly with Deny, see Canonicalization Problems Using Deny in the Using the Deny Method topic.
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In the .NET Framework
versions 1.0 and 1.1, identity permissions cannot have an Unrestricted permission state value. In the .NET Framework version 2.0, identity permissions can have any permission state value. This means that in version 2.0, identity permissions have the same behavior as permissions that implement the IUnrestrictedPermission interface. For information on executing version 2.0 applications with version 1.1 CAS policy, see <legacyV1CASPolicy> Element.
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