Viscosity

Viscosity is a client application for connecting to OpenVPN servers. It is aimed at people who already have access to an OpenVPN endpoint, whether that is a company gateway, a self-hosted router or a commercial provider, and who want to manage those connections through a normal Windows interface instead of editing configuration files by hand. Existing .ovpn configurations can be imported, and connections can also be built from scratch in the editor.

The connection editor exposes the settings that usually live in an OpenVPN config file: certificates and keys, authentication method, routing, proxy settings and DNS behaviour. DNS can be handled in full or split mode, so that only queries for the remote network are sent through the tunnel. Several connections can run at the same time, IPv6 is supported end to end, and there is an obfuscation option intended for networks that block recognisable VPN traffic. Stronger authentication setups, including smartcards and hardware tokens, are also covered.

While connected, the application reports throughput and connection details in real time and keeps the OpenVPN log accessible, which makes it useful for diagnosing why a tunnel fails to come up. Connections can be driven from scripts through VBScript or batch files on Windows and AppleScript on macOS, and administrators can bundle prepared connection settings for distribution to staff.

This is a client only: it provides no VPN service or servers of its own, so it is not a substitute for a subscription VPN product and is of no use without server details to connect to. It is also tied to the OpenVPN protocol, so anyone who needs WireGuard or a vendor-specific protocol should look elsewhere. Windows 10 or later is required for the current release, with older builds offered separately for earlier systems.