usr/src/share/man/man4/lo.4

.\" Copyright (c) 1983 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"     @(#)lo.4        6.1 (Berkeley) %G%
.\"
.TH LO 4 ""
.UC 5
.SH NAME
lo \- software loopback network interface
.SH SYNOPSIS
.B pseudo-device loop
.SH DESCRIPTION
The
.I loop
interface is a software loopback mechanism which may be
used for performance analysis, software testing, and/or local
communication.   By default, the loopback interface is
accessible at address 127.0.0.1 (non-standard); this address
may be changed with the SIOCSIFADDR ioctl.
.SH DIAGNOSTICS
\fBlo%d: can't handle af%d\fP.  The interface was handed
a message with addresses formatted in an unsuitable address
family; the packet was dropped.
.SH SEE ALSO
intro(4N), inet(4F)
.SH BUGS
It should handle all address and protocol families.
An approved network address should be reserved for this
interface.