The 4 Main Types of VPN

A remote access VPN lets you use the internet to connect to a private network, such as your company’s office network.

The internet is an untrusted link in the communication. VPN encryption is used to keep the data private and secure as it travels to and from the private network.

When to Use a Remote Access VPN

There are different ways a remote access VPN can be used, for example:

• A business traveler could use a remote access VPN to connect to their company’s network from the WiFi in the hotel lobby. They can access all the same files and software they would have in the office. The VPN also protects the data from anyone snooping on the public WiFi.

• Somebody working from home could use a remote access VPN to access the company’s network from home. Their computer works as if it was connected to the company network in the office, and data is protected as it goes through the public internet.

How Remote Access VPNs Work

To use a remote access VPN on your device you typically need to install client software or configure your device’s operating system to connect to the VPN. There also needs to be a VPN server on the network end of the connection.

There can be many client devices, as many different users can connect to the VPN server. Between them, the client software and VPN server manage the VPN connection.

Here’s how a remote access VPN works:

1. First, the VPN server checks that the user is allowed to access the network.

   This might require the user to enter a password, or use biometrics such as a fingerprint to identify themselves. In some solutions, security certificates can be used to automatically authenticate the user in the background, enabling a faster connection. This is particularly helpful where the user needs to connect to multiple VPN servers – to access different site networks, for example.

2. Once the user is authenticated, the client and server establish an encrypted tunnel between them.

   This is a wrapper of encryption that protects the traffic going over the internet. There are lots of different VPN protocols that can be used to set up the encryption tunnel: IPsec and SSL are two that are often used.

3. The user can now access resources through the VPN server.

   This gives them access to a company’s internal network to access files or software.

Examples of Remote Access VPNs

Examples of remote access VPNs for business include:

• Access Server by OpenVPN, which is free for up to two simultaneous VPN connections.
• Cisco AnyConnect, which integrates with Cisco’s enterprise security solutions.
• Perimeter 81 Next-Gen Secure VPN Solutions.

A personal VPN service connects you to a VPN server, which then acts as a middleman between your device and the online services you want to access.

The personal VPN – sometimes also called a ‘consumer’ or ‘commercial’ VPN – encrypts your connection, hides your identity online, and lets you spoof your geographic location.

A personal VPN service differs from a remote access VPN in that it doesn’t give you access to a private network.

Instead, a personal VPN works by giving you access to the public internet, but over an encrypted connection.

When to Use a Personal VPN Service

There are several reasons to use a personal VPN. Some of the most popular ones include:

• Streaming online movies and TV shows unavailable in your geographic location. For example, you can connect to a VPN server in USA and access American Netflix, which is one of Netflix’s largest content libraries.

• Evading web censorship and surveillance in authoritarian states, such as China and the UAE. A VPN gives you access to content blocked by national firewalls, and hides your web traffic from state surveillance systems.

• Hiding your IP address to protect yourself from targeted Distributed Denial of Service (DDoS) attacks. Gamers increasingly use short but intense DDoS attacks to block competitors and secure an unfair victory. A VPN helps avoid this.

• Safeguarding your internet privacy by stopping your internet service provider (ISP), governments, hackers, and anyone else from snooping on your activity. ISPs sometimes throttle (or slow down) your connection if they can see you are streaming games or movies. Using a VPN stops them from knowing what you’re doing online and prevents them from throttling your internet connection.

For a more extensive list, read our dedicated guide to what VPNs are used for.

How Personal VPNs Work

Here’s how a personal VPN works:

1. Install software from your VPN service provider onto your device.

   Personal VPN apps are available on all sorts of devices, including smartphones. Alternatively, you can install the VPN software on your router to protect all the devices that connect to it.

2. Connect to a server in your VPN provider’s network.

   Personal VPNs tend to have large server networks to choose from. If you just want to protect your privacy, connect to a local server for the fastest speeds. If you want to unblock streaming content, choose a server in the country where that content is accessible.

3. Browse the internet like normal.

   While connected to the VPN, all your internet traffic goes through the service provider’s server. Your connection is encrypted, your IP address is hidden, and you can access geographically restricted content from other countries.

Examples of Personal VPN Services

We’ve tested over a hundred personal VPNs since 2016. Currently, our three highest-rated VPNs are:

1. ExpressVPN
2. NordVPN
3. Private Internet Access

While remote access VPNs let you connect to a local network from anywhere, they do assume that the user will stay in one location. If the user disconnects, the IP tunnel closes.

A mobile VPN is a better option than a remote access VPN if the user is unlikely to have a stable connection, on the same network, for the entire session.

With a mobile VPN, the VPN connection persists even if the user switches WiFi or cellular network, loses connectivity, or switches their device off for a while.

When to Use a Mobile VPN

Mobile VPNs tend to be used to ensure consistent availability for mobile workers, or for the convenience of having a VPN that tolerates connection changes. For example:

• Firefighters and police officers can use a mobile VPN to stay connected to applications such as vehicle registration databases, automatic vehicle location, and computer-aided dispatch, even as they travel around.

• Professionals working from home in an area with poor connectivity could use a mobile VPN to maintain VPN access to the office all day, even when the connection is lost.

How Mobile VPNs Work:

Here’s how a mobile VPN works:

1. The user connects to the VPN and is authenticated.

   Authentication options might include passwords, physical tokens such as smart cards, or biometric devices such as fingerprint scanners. In some cases, certificates can be used so the authentication happens automatically in the background.

2. The VPN tunnel is established between the user’s device and the server.

   In a remote access VPN, the VPN tunnel connects to the device’s physical IP address, which is tied to its internet connection. In a mobile VPN, the VPN tunnel connects to a logical IP address, which is tied to the device, and so is independent of the internet connection.

3. The VPN connection persists as the user switches between different networks.

   If the user is mobile, they might switch between networks (for example, between cellular or WiFi networks). Their physical IP address can change, but the logical IP address the VPN tunnel uses stays the same. The virtual network connection remains intact, so the user can continue working seamlessly as long as they have any connection.

   If the device is turned off to preserve the battery life, the VPN connection is still available when the device is switched back on.

Examples of Mobile VPNs

Mobile VPN examples include:

• Bittium SafeMove Mobile VPN: automatically connects users and provides seamless roaming.
• Radio IP software: enables mobile VPNs across all wireless network technologies.

Whereas a remote access VPN is designed to let individual users connect to a network and use its resources, a site-to-site VPN joins together two networks on different sites.

If a company had two offices on the east coast and west coast, for example, a site-to-site VPN could be used to combine them into a single network.

Different technologies can be used to implement a site-to-site VPN. These include IPsec, Dynamic MultiPoint VPN (DMVPN), and L3VPN.

When to Use a Site-to-Site VPN

Depending on who owns the networks being joined, there are generally two different forms of site-to-site VPN:

• Intranet-Based VPN: When the networks being connected belong to a single company, the combined VPN is known as an intranet-based VPN. This enables a company to establish a single wide area network (WAN) that spans two or more of its offices. Users in the company can access resources from other sites as easily as if they were on their own site.

• Extranet-Based VPN: When the networks being connected belong to different companies, the combined VPN is known as an extranet-based VPN. An extranet VPN is used, for example, when a company wants to connect to its supplier’s network, so they can trade more efficiently.

How Site-to-Site VPNs Work

There are three main ways a site-to-site VPN can be implemented:

1. Using an IPsec tunnel
2. Using a Dynamic MultiPoint VPN (DMVPN)
3. Using a Layer 3 VPN (L3VPN)

IPsec tunnel

An IPsec tunnel can be used to join sites together, in much the same way it connects individuals to a private network within remote access VPNs.

In this case, however, the VPN is implemented by routers at the two or more sites that are connecting to each other. For this reason, it’s sometimes also called a router-to-router VPN.

Whereas a remote access VPN creates a tunnel for one device to connect to the private network, with a site-to-site VPN, the IPsec tunnel encrypts the traffic between the connected networks. This can take two forms:

1. A route-based IPsec tunnel allows any traffic between the networks through. It’s like wiring the networks together.
2. A policy-based IPsec tunnel sets up rules that decide what traffic is allowed through, and which IP networks can talk to which other IP networks.

IPsec tunnels can be built using most firewalls and network routers.

Dynamic MultiPoint VPN (DMVPN)

The problem with IPsec tunnels is that IPsec connects two points to each other. In a site-to-site network, for example, IPsec could be used to connect two routers to each other.

That doesn’t scale well in large companies with thousands of sites, where thousands of connections might need to be established.

Instead, Cisco’s Dynamic MultiPoint VPN (DMVPN) technology offers a solution. It enables sites to connect to the DMVPN hub router using dynamic IP addresses.

The network architecture is a hub-and-spoke design, which reflects the fact that most traffic goes between branch sites (spokes) and the main site (hub), rather than between one branch and another.

That said, it’s still possible for branch sites to connect to each other using a DMVPN. It just takes a little additional configuration.

MPLS-based Layer 3 VPN (L3VPN)

The IPsec and DMVPN approaches both sit on top of the internet, which means they can’t offer consistent or guaranteed performance.

By contrast, Multi-Protocol Label Switched (MPLS) Layer 3-based VPNs can provide a guaranteed quality of service, with global connectivity. This is because MPLS is a way of routing packets across a network via any transport medium (such as fiber, satellite, or microwave) and any protocol.

Service providers can therefore use MPLS to create a Layer 3 VPN. The ‘Layer 3’ refers to the OSI network model, which uses multiple layers to explain how communications are converted between electrical, radio, or optical signals into application data. Layer 3 means the VPN is created in what’s called the ‘network layer’.

While some large companies might set up their own MPLS VPNs, they’re usually created by communications service providers.

The service provider can create a separate virtual network for each customer, which it resells as a wide area network (WAN). The virtual networks are isolated from each other, even though they may share some of the same physical network resources.

If you buy a WAN service from a communications service provider, it could well be using an MPLS L3VPN, without you necessarily knowing.

With an MPLS VPN, it’s possible to prioritize certain types of high-priority traffic, such as voice traffic, to ensure a better quality of service. The route through the network can be precisely controlled, too, to enable consistent and well-optimized performance.

Private WAN services are expensive, so there’s a trend for companies to decommission MPLS services in favor of cheaper internet-based VPNs. The main exceptions are for situations where any latency is critical – for example, in applications that detect faults and outages in the power grid.

Examples of Site-to-Site VPNs

Examples of the different types of site-to-site VPN include:

• Access Server by OpenVPN, can be used to create a site-to-site VPN.
• Cisco’s Dynamic Multi Point VPN (DMVPN), is described in more detail here.
• Nokia provides instructions for setting up a VPRN service (L3VPN).