Introduction to VPN:

Virtual private networks are secured private network connections, built on top of publicly accessible infrastructure, such as the Internet or the public telephone network. VPNs
typically employ some combination of encryption, digital certificates, strong user authentication and access control to provide security to the traffic they carry. They usually provide connectivity to many machines behind a gateway or firewall.

A VPN (Virtual Private Network) enables a specific group of users to access private network data and resources securely over the Internet or other networks. Although often using public networks, a VPN inherits the characteristics of a private network, hence the acronym of "Virtual" Private Network. It's the concurrent use of tunneling, encryption, authentication, and access control over a public network that basically characterizes a VPN.

Types of VPN:

One can identify three basic types of VPN:

Intranet VPN: This type of VPN is "client transparent". It is usually implemented for networks within a common network infrastructure but across various physical locations. For instance several buildings may be connected to a data center, or a common mainframe application that they can access securely through private lines. Those VPNs need to be especially secured with strong encryption and meet strict performance and bandwidth requirements. They must remain easily upgradeable since many users may be added to the load down the road (additional locations or applications).

Remote Access VPN: Here VPN is "client initiated". It is intended for remote users that need to connect to their corporate LAN from various points of connections. It is intended for salesmen equipped with laptops and telecommuters that will connect intermittently from vary diverse locations (homes, hotels, conference halls...). The key factor here is flexibility as performance and bandwidth are usually minimal and less of an issue. More than encryption, authentication will be the main security concern.

Extranet VPN: In this case VPN uses the Internet as main backbone. It usually addresses a wider scale of users and locations, enabling customers, suppliers and branch offices to access corporate resources across various network architectures. They rely on VPN standards such as IPsec to ensure maximum compatibility while trying not to overly compromise security.

The most common reasons to use a VPN are:

• Reduce the costs of telecommunications (especially long distance phone charges) by using the Internet to carry traffic
• Reduce telecommunications costs by minimizing the number of lines accessing a corporate site
• Save operating expenses by contracting VPN anagement and equipment costs to a service provider

Software configuration management (SCM)
Effective software configuration management (SCM) strategies promote a healthy, teamoriented culture that produces better software. We are using two (SCM) tools, namely:

• PERFORCE
• VSS