IGD
also: UPnP IGD, Universal Plug and Play Internet Gateway Device
IGD (Internet Gateway Device) is a UPnP protocol that allows applications to automatically configure port forwarding and network settings on a router without manual intervention.
IGD stands for Internet Gateway Device and is part of the Universal Plug and Play (UPnP) standard. It enables applications running on a local network to automatically discover and configure port mappings on a router, eliminating the need to manually log into the router's admin interface.
When an application needs to accept incoming connections from the internet, it can use IGD to request that the router forward traffic on a specific port to the application's IP address and port. For example, a torrent client or VoIP application might use IGD to automatically open port 6881 without requiring the user to access the router's configuration panel.
On Linux, tools like miniupnpc provide command-line access to IGD functionality. Many applications check for UPnP/IGD support at startup and attempt automatic port mapping if available, falling back to manual configuration if the feature is unavailable or disabled.