A site-to-site virtual private network (VPN) refers to a connection set up between multiple networks. This could be a corporate network where multiple offices work in conjunction with each other or a branch office network with a central office and multiple branch locations.
Site-to-site VPNs are useful for companies that prioritize private, protected traffic and are particularly helpful for organizations with more than one office spread out over large geographical locations. These businesses often have to access resources housed on a primary network, which could include servers that facilitate email or store data. In some instances, a server may be the operational hub of an application essential to the company’s business. A site-to-site VPN can, in that case, give all sites full access to the application—as if it were housed within their physical facility.
The history of site-to-site VPNs intersects, in many ways, with the history of the internet itself. Site-to-site VPNs were a forbearer of what we now know as the internet. They were first made possible through the use of the original packet switching network named Advanced Research Projects Agency Network (ARPANET), as well as the initial uses of Transmission Control Protocol/Internet Protocol (TCP/IP).
