A private network uses private Internet Protocol addresses, meaning they aren’t allocated to any particular organization. Virtual private networks are private computer networks that connect remote sites with a public network, according to Microsoft Technet. This means that VPNs must authenticate remote users to prevent the unauthorized access of private information. The increasing use of mobile devices also presents a challenge when networking sites together with a VPN.
The Internet Engineering Task Force sets standards regarding private IP addresses, which are typically used in homes and small businesses. Larger businesses may also use VPNs in the form of local area networks when global addresses are either unavailable or not required for that network application. The first version of IP to be widely deployed was IPv4, which defined private IP addresses to reduce the allocation of public IP addresses. IPv6 is the most current version of IP, which also uses private IP addresses. The IP packets addressed by private IP addresses can’t be transmitted to the public Internet. A private network doesn’t need approval from a regional Internet registry to use private IP addresses. However, private networks do require some means of connecting to the Internet such as a proxy server or network address translator gateway.
The VPN Consortium describes a VPN as routing virtual connections from the private network through the Internet to the remote site by using dedicated connections or encryption to ensure that it can’t be read by anyone who intercepts the data. These connections comprise a wide area network between the sites that belong to the VPN. These measures allow a remote computer to communicate with the host computer on the VPN as if it were part of the VPN. The remote computer has all of the functionality of the VPN, and is subject to all of the VPN’s management and security policies. The remote computer also has access to extended resources on the VPN.
A VPN establishes connections between computers with remote access or site-to-site access. Remote access involves connecting an individual computer to a VPN, whereas site-to-site access connects another network to the VPN. Large businesses typically use remote-access VPNs to provide employees access to the corporate intranet from remote sites such as home or while traveling. The most common use for site-to-site VPNs is to allow employees in different locations to share a single virtual network. Another use of VPNs is to connect two similar networks by using a different network. A common example of this type is to connect an IPv4 network to another IPv4 network through an IPv4 network.