AllowedPaths=path list

This variable contains a comma-separated list of absolute paths that are allowed for use by the site. It is similar to setting AbsolutePath to true, but limited only to specified paths. Path list can contain paths outside site's wwwroot directory, paths located on other disks or even other network computers.
It is very useful on shared servers where web site needs an access to files outside wwwroot directory but you can not set AbsolutePath to true due to security reasons.