tunaforward

tunaforward is a term used in computer networking to describe a component or mode of operation that forwards network traffic through a TUN device to a remote endpoint. The name combines TUN, a virtual network kernel interface, and forward, reflecting its role in routing packets from one network namespace or interface into a tunnel.

Functionality: It typically operates in user space or kernel space, captures packets from an application or interface, injects them into a TUN device, and forwards them via a tunnel (VPN, SSH, IPsec) to a peer. It may apply address translation, routing rules, or filtering. The approach enables software-defined routing that can bypass or augment host-based forwarding, depending on the topology and policy.

Origins and usage: The term is not standardized; it appears in open-source documentation and project READMEs to describe modules that implement packet forwarding through a TUN device. It is commonly used in VPN-like systems and network emulation tools, and is related to, but distinct from, general IP forwarding and NAT. Real-world implementations often rely on Linux TUN/TAP devices and netlink for configuration, and may be integrated with software such as OpenVPN, WireGuard, or custom user-space forwarders.

See also: TUN/TAP, VPN, IP forwarding, NAT, user-space networking, netlink.