The xrootd data server, part of the Scalla Software Suite, allows external
client access to data protected by firewalls using proxy servers. Since
xrootd is a peer-to-peer architecture servers can be recast as clients,
making it natural to provide a proxy data service. This talk describes the
xrootd proxy mechanism, how proxy clusters can be defined, and future
direction to use proxy services to provision peer cross-domain data
networks.