The loop device is a software loopback network interface; see if.4n for a general description of network interfaces.
The loop interface is used for performance analysis and software testing, and to provide guaranteed access to Internet protocols on machines with no local network interfaces. A typical application is the comsat.8c server which accepts notification of mail delivery through a particular port on the loopback interface.
By default, the loopback interface is accessible at Internet address 127.0.0.1 (non-standard); this address may be changed with the SIOCSIFADDR ioctl.
Created by unroff & hp-tools. © by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97