Virtual Private Networks

A virtual private network takes a public, shared connection such as the internet and uses it to carry private traffic. Data travelling between your device and the VPN's endpoint is wrapped in encryption, so anyone watching the network in between sees scrambled information rather than readable emails, files or passwords. The idea started in the business world, but it has become a common tool for households too.

How the tunnel works

When a VPN client connects, it establishes an encrypted link, often described as a tunnel, to a server run by your company or a VPN provider. From then on, traffic is encrypted on your device, passes through the tunnel and is decrypted only at the other end. To the wider network, it looks like one stream of unreadable data going to a single destination.

Different protocols handle this job, including IPsec, OpenVPN and WireGuard. They vary in speed, compatibility and configuration, but all aim to keep data private and confirm that both ends of the connection are who they claim to be.

Two common business setups

Remote access for staff

The original purpose of VPNs was to let people outside the office reach internal resources safely. An employee working from home or at a client site connects to the company VPN and can then use shared drives, internal applications or printers as if they were plugged into the office network. The business keeps sensitive systems off the open internet while still supporting flexible work.

Site-to-site links

Organisations with more than one location can join their networks with a permanent VPN connection between routers. Branch offices then share resources over the internet without paying for dedicated private lines, and users often do not even notice the link is there.

Where a VPN helps at home

• Public Wi-Fi: cafés, hotels and airports often run open networks. A VPN adds a layer of protection against snooping on those connections.
• Working from home: many employers require staff to connect through the company VPN before opening work systems.
• Reaching your own network: some home routers and network storage devices offer a built-in VPN, so you can reach your own files while travelling.
• Privacy on shared networks: encryption keeps the details of your browsing out of view of others on the same network.

The limits of a VPN

A VPN is a useful layer, not a complete security plan. It does not stop malware you download yourself, protect an account with a weak or reused password, or make a phishing email harmless. A commercial VPN provider can also see traffic that leaves its servers, so it pays to choose one with a clear privacy policy and a good reputation. Encryption can slow connections slightly, depending on the protocol and the distance to the server.

Used alongside updated software, strong unique passwords and two-factor authentication, a VPN makes everyday connections considerably safer. For businesses, it remains one of the simplest ways to give remote staff secure access, and for households it is a sensible companion whenever the network in use is not your own. As with any tool, use it in line with your workplace policies and local rules.