LogMeIn Hamachi is a virtual private network (VPN) application developed and released in 2004 by Alex Pankratov.

Client software adds a virtual network interface to a computer, and it is used for intercepting outbound as well as injecting inbound VPN traffic.

Outbound traffic sent by the operating system to this interface is delivered to the client software, which encrypts and authenticates it and then sends it to the destination VPN peer over a specially initiated UDP connection.

When establishing tunnels between the peers, Hamachi uses a server-assisted NAT traversal technique, similar to UDP hole punching.

This makes it possible to use LAN protocols that rely on IP broadcasts for discovery and announcement services over Hamachi networks.