The Internet is increasingly used as a means for exchanging large amounts of spatial data. Professional data centres have found secure ways to share their data resources with peers and third-party users, either as a free service or as a commercial activity. Ranging from a simple download of tables to online queries of distributed SQL databases, the role of the Internet is undeniable. It is obvious that extended security measurements are needed in order to share data over the Internet, such as a DMZ or ‘demilitarized zone’ and firewalls. Increasingly, dedicated server-side applications contribute to a straightforward data retrieval procedure.