Communications to a server over an in-band communications channel are monitored for requests to access a file. Based on the communications, a request to access a particular file stored by the server is identified. Security and/or audit rules are identified based on the request. A determination is thereafter made that the security and/or audit rules require evaluation of classification information for contents of the requested file. Thus, a determination is made as to whether classification information for the contents of the particular file is available, such as determining whether the classification information is stored in a local classification cache. Responsive to a determination that the classification information is not available, classification information is obtained for the contents of the particular file using an out-of-band communications channel. Thereafter, processing with respect to the request to access the particular file is performed based on the obtained classification information and the one or more security and/or audit rules.