NAME
lo —
software loopback network
interface
SYNOPSIS
loop |
DESCRIPTION
The loop interface is a software loopback
mechanism which may be used for performance analysis, software testing,
and/or local communication. As with other network interfaces, the loopback
interface must have network addresses assigned for each address family with
which it is to be used. These addresses may be set or changed with the
SIOCSIFADDR
ioctl(2).
The loopback interface should be the last interface configured, as protocols
may use the order of configuration as an indication of priority. The
loopback should
never be
configured first unless no hardware interfaces exist.
DIAGNOSTICS
- lo%d: can't handle af%d.
- The interface was handed a message with addresses formatted in an unsuitable address family; the packet was dropped.
SEE ALSO
HISTORY
The lo device appeared in
4.2BSD.
BUGS
Previous versions of the system enabled the loopback interface automatically, using a nonstandard Internet address (127.1). Use of that address is now discouraged; a reserved host address for the local network should be used instead.