loopbackliidest

Loopbackliidest is a virtual network interface that routes traffic back to the host rather than onto a physical network. It provides a means for software running on a single machine to communicate with itself and with other local processes with minimal latency.

Traffic addressed to the loopback addresses is processed entirely within the host. In IPv4, the address 127.0.0.1 (and the 127.0.0.0/8 block) is reserved for loopback, while IPv6 uses ::1. The loopback interface is typically always present in the kernel and does not correspond to a physical network card.

Applications include software testing, development, and internal system services; used by databases, web servers, and message brokers to listen on localhost and to exchange data with local clients without exposing services to external networks.

Configuration and limitations: The loopback interface has its own virtual network settings, such as MTU, and traffic cannot be reached from other hosts. In virtualization and containerized environments, loopback traffic may be scoped to a specific namespace or virtual router.

Etymology and usage: In Estonian-speaking contexts, loopbackliidest literally means the loopback interface. In English technical writing the term loopback interface or loopback is used. The article treats loopbackliidest as a direct translation of the same concept.