Using a Virtual Private Network (VPN) is the most secure option for implementing replication over the Internet. VPNs include client software so that computers connect over the Internet (or in special cases, even an intranet) to software in a dedicated computer or a server. Optionally, encryption at both ends as well as user authentication methods keep data safe. The VPN connection over the Internet logically operates as a Wide Area Network (WAN) link between the sites.
A VPN connects the components of one network over another network. This is achieved by allowing the user to tunnel through the Internet or another public network (using a protocol such as Microsoft Point-to-Point Tunneling Protocol (PPTP) available with the Microsoft® Windows NT® version 4.0 or Microsoft Windows® 2000 operating system, or Layer Two Tunneling Protocol (L2TP) available with the Windows 2000 operating system). This process provides the same security and features previously available only in a private network.