.Dd May 27, 2017
.Dt LO 4
.Os
.Sh NAME
.Nm lo
.Nd loopback network interface
.Sh SYNOPSIS
.Nm /dev/lo Ns Ar X
.Sh DESCRIPTION
.Nm
is a loopback network interface that receives what is sent on it, used for
communication within the local host.
.Nm
is implemented in software and the packets sent on it are not transmitted on the
network.
.Pp
The
.Xr kernel 7
creates the
.Sy lo0
network interface on boot and configures it with the
.Xr inet 4
address
.Dv 127.0.0.1
in the subnet
.Dv 127.0.0.0/8 .
Packets with source or destination outside this subnet are dropped.
.Sh SEE ALSO
.Xr kernel 7 ,
.Xr ifconfig 8
.Sh CAVEATS
The default
.Xr inet 4
configuration
of the
.Sy lo0
network interface must not be changed or local loopback communication may fail.