A proxy server for downloading a data file for a client, such as an email client or web browser, including: a external proxy for downloading the data file for the client from an external server over a network, based on profile data associated with the client stored on the proxy server; a memory module for storing the data file; and an internal proxy for transferring the data file to the client when requested by the client. The external proxy operates asynchronously to the internal proxy, and the proxy server operates transparently with respect to the client.