What Is a Site-to-Site VPN and Do You Need One?

Dusan Vasic

Updated: May 6, 2023

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“What is a site-to-site VPN?” is a question we often get asked by our readers, so in today’s post, we’ll discuss the benefits of these VPNs that allow you to securely connect two networks, what to look for when choosing one, and the various available types of VPNs. 

VPN Types

If you’re exploring what type of VPN you need for your organization, or if you simply want to learn more about the technology before purchasing a subscription, you should know there are three main types of VPNs:

• Remote Access VPN. This VPN allows employees to securely connect to the company’s network when they’re not in the office.
• Peer-to-Peer VPN. Used to connect two computers directly, without the need for an intermediary.
• Site-to-Site VPN. Great for businesses with multiple offices or people who want to secure access to their home computers while they’re away.

Remote Access VPNs

More than likely, at some point, you had to work from home and needed to access your office workstation. For that, you needed a remote access VPN. This type of VPN is also known as a virtual private dial-up network (VPDN). It uses the public internet to connect to a private corporate network. The advantage of the VPDN is that it can be used from any location, meaning employees can access their company’s servers and files from anywhere in the world.

This type of remote VPN connection creates an experience similar to a local network connection with ethernet cables. The user’s computer is physically connected to the corporate network, and all traffic passes through the company’s servers. Remote employees thus have access to the same resources as if they were in the office.

The disadvantage of using a VPDN is that it can be expensive as it requires setting up dedicated hardware and software on your company’s network.

Peer-to-Peer VPNs

If you want to securely connect two computers without the need for a third party, you can use a peer-to-peer VPN. This type of VPN is also called a host-to-host VPN or an intranet bridge.

With a peer-to-peer VPN, two computers create an encrypted tunnel between them. This tunnel allows them to share files and applications and access the other computer’s resources. It’s easy to set up and, depending on the deployment method, you can host your own VPN server at no extra cost. 

The disadvantage of using a peer-to-peer VPN is that it can be slow, not as secure as a site-to-site VPN, and has limited functionality. For example, such a setup wouldn’t let you access streaming services from other countries like VPNs that specifically unlock Netflix.

Site-to-Site VPNs

Finally, let’s take a look at how a site-to-site VPN works and what its advantages and downsides are.

A site-to-site VPN consists of two parts: a VPN gateway and a VPN client. A VPN gateway is a device that connects devices or networks together, while a VPN client is most often an application that connects to the VPN gateway. However, it also can be a piece of hardware with installed VPN software. 

You create a tunnel between two networks when you set up a site-to-site VPN. The tunnel is encrypted and secure, and it allows traffic to flow between the networks. This means your communication is safe from prying eyes.

The VPN gateway and the VPN client use a standard encryption key to encrypt and decrypt the traffic going through the tunnel. This key is known as the shared secret, and it’s something you need to configure on both devices.

Site-to-Site VPN vs. Remote Access VPN

At this point, you might be wondering what’s the difference between a site-to-site VPN and a remote access VPN. Unlike remote VPN, a site-to-site VPN connects two networks rather than a single device to an external network. For example, you might use a site-to-site VPN to connect your office and home network. This would allow you to access the files and applications on your office network from home.

Pros and Cons of Site-to-Site VPNs

Site-to-site VPNs come with a set of distinct advantages, but there are some downsides to consider as well. In this section, we analyze both to help you decide if this is the best solution for you.

Advantages of Site-to-Site VPNs

• Security. A site-to-site VPN establishes a secure connection between two networks. This makes it ideal for businesses that want to connect multiple company offices. The added security is also helpful for people who want to improve the safety of their home network.
• Cutting costs. A site-to-site VPN can save your business money by allowing you to use your existing network infrastructure.
• Convenience. A site-to-site VPN makes it easy for employees to access the resources on the company’s network from anywhere in the world. However, if you’re shopping for a VPN for noncommercial use, renowned VPN services offer much more to regular users.
• Simplified network architecture. Organizations with a complex network infrastructure can use a site-to-site VPN to simplify their network. Traffic among multiple LANs can be routed through the VPN, eliminating the need for complex network topology.

Disadvantages of Site-to-Site VPNs

• Latency. If you expect a lag-free experience when connecting through a site-to-site VPN tunnel, you may end up disappointed. The latency of a site-to-site VPN can be high, primarily if the two networks are located in completely different parts of the world.
• Bandwidth usage. This type of VPN can use up a lot of bandwidth, especially if there is high traffic between the two networks.
• Complex setup. Connecting two virtual private networks is a challenge for most users. It also requires extensive planning and testing.
• Limited flexibility. The networks you can connect together with a site-to-site VPN are limited to what’s physically possible. You can’t use a site-to-site VPN to connect two networks separated by a firewall. That’s why a secure access service edge is often used as an alternative.
• Maintenance. A site-to-site VPN requires ongoing maintenance to keep it running smoothly. This includes regularly updating the encryption and authentication keys.

Site-to-Site VPN Alternatives: Secure Access Service Edge 

If you don’t want to set up a site-to-site VPN, you can use a secure access service edge instead. A SASE is a cloud-based service that provides secure remote access to your network.

It combines a remote access VPN with the security features you’d expect from a corporate firewall, such as threat hunting and detection, next-gen antivirus, and more.

If you’re concerned about company data being handled remotely, then investing in a SASE system is likely the best option for dealing with a remote workforce. It gives you all the benefits of your office network security through cloud infrastructure.