Site-to-Site VPN: what it is and how it works

Site-to-Site VPN: what it is and how it works

Site-to-Site VPN (site-to-site VPN) describes the connection between different networks, such as corporate networks with multiple offices or a branch network with a central office and several branches.

This type of VPN  useful for companies that value the privacy and security of transmitted traffic, especially for organizations with multiple offices scattered over large geographic areas. They are designed to gain access to resources located on the main network, such as servers for email or data storage. Sometimes a server can be a key component of a service that is important to a company's business. In this case, Site-to-Site VPN can provide all offices with full access to its resource, as if it were located in their physical premises.

From origins to the present: Site-to-Site VPN

The history of Site-to-Site VPN is closely related to the history of the Internet. These networks were the forerunners of the modern Internet and were made possible by the use of the original ARPANET packet switching network and TCP/IP protocols. TCP/IP defines the organization of data in the form of packets, assigns them addresses, and ensures their transmission and reception between different computers on the Internet. Before the launch of the modern Internet, computers were connected to each other through private networks and TCP/IP. Thus, Site-to-Site networks became the basis for the modern Internet.

Modern VPNs have become popular due to the desire of users to hide their IP-addresses and ensure security when surfing the Internet. Hidden IP address allows you to download torrents without revealing your identity and access blocked content. Additionally, when using a public network you have to deal with cyber attacks, but a VPN provides a more secure, encrypted connection. These characteristics have made private VPNs the preferred choice for individual users.

However, VPNs created for one or more users at the same time cannot meet the needs of a large organization. In many cases, large companies need to transfer large amounts of data between locations quickly and securely, and regular VPNs will not be able to cope with this task.

How to create a VPN between sites

Setting up a VPN between sites includes determining the method of data transfer and choosing a method to ensure its protection. This can be done using a VPN over the Internet or a VPN with MPLS.

VPN over the Internet uses the organization’s already existing network with the public Internet. To do this, a tunnel is created between two networks using three main components:

  1. main network in one place;
  2. satellite network in another location;
  3. a tunnel with security gateways at both ends.

This tunnel operates over a physical Internet connection, protecting transmitted data from unauthorized access. In this case, data encryption occurs at the first gateway, and decryption occurs at the second. It is also important to mention the use of a firewall for additional network protection.

MPLS VPN depends on the infrastructure provided by the VPN provider. It works through tags that direct data to the desired location, instead of using IP-addresses. To set up an MPLS VPN, you need to set up a broadband IP network and then equip each location with an MPLS-compatible switch to enable data to be sent over MPLS.

Both VPN options allow you to securely exchange data between different locations, but each has its own characteristics and configuration requirements.

What to consider when implementing Site-to-Site VPN

When deciding whether to implement a VPN between sites, several factors should be taken into account. In some cases, a regular IPsec is sufficient for communication between two or more locations. However, there are several situations that may prompt a company to use VPN connections:

  • number of locations;
  • company size;
  • distance between each location;
  • resources available for sharing between locations.

In most cases, site-to-site VPN is a good solution if a company has multiple locations, each of which requires employees to access resources provided by the main office. Using a VPN between sites in such situations, you can ensure secure access for employees to shared resources.

Let's say you have a company with a head office in New York and several branches: one in Shanghai, one in France and another in Switzerland. Each branch employs from 15 to 20 employees. The company's email server is located on a central server, and there is also a data server that stores important marketing materials and confidential information. Using a VPN between sites, you will provide employees with access to shared resources and protect data using encryption, which will ensure the safety of information from attacks.

Private VPN server:

Private VPN server and VPN between sites are interconnected through the concept of virtual private network, but at the same time, they represent different types of effective VPN solutions.

A private VPN server is usually configured on the end user's computer or device, such as a home PC or router. It is commonly used to provide secure and encrypted Internet access or to protect user privacy when using public networks. Provides remote Internet access for one or more devices such as smartphones, laptops or tablets.

Therefore, for each user, an appropriate and reasonable option for ensuring complete freedom, privacy and security on the Internet is the decision to buy a private VPN-server on Private VPN server.

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