NAT traversal is a mechanism that facilitates the communication between devices behind network address translation (NAT) devices and devices outside the NAT network.

NAT devices allow several devices to share one public IP address. They function by altering the origin and destination of the IP address packet’s IP header as it transmits through the NAT device. Unfortunately, this can present issues for some network traffic, like VPN traffic.

However, the NAT traversal technique enables VPN traffic to transverse the NAT device and create a VPN connection even when the server and VPN client are behind different NAT devices.

VPN Traffic Traversing NAT Devices

How Does NAT Traversal Work?

NAT traversal uses NAT to establish communication between two endpoints. It uses several techniques to enable the endpoints to communicate directly, which is helpful for peer-to-peer applications that require direct communication for optimal performance. 

NAT transversal methods to bypass NAT device restrictions include: