lo(7)                                                                 lo(7)

NAME
     lo - software loopback network interface

SYNOPSIS
     d = open ("/dev/loop", ORDWR);

DESCRIPTION
     The loopback device is a software datalink provider (interface driver)
     that returns all packets it receives to their source without involving
     any hardware devices. It is a STREAMS device conforming to the
     datalink provider interface (DLPI). See if(7) for a general descrip-
     tion of network interfaces.

     The loopback interface is used to access Internet services on the
     local machine. Because it is available on all machines, including
     those with no hardware network interfaces, programs can use it for
     guaranteed access to local servers. A typical application is the
     comsat(1M) server which accepts notification of mail delivery from a
     local client. The loopback interface is also used for performance
     analysis and testing.

     By convention, the name of the loopback interface is lo0, and it is
     configured with Internet address 127.0.0.1. This address may be
     changed with the SIOCSIFADDR ioctl().

SEE ALSO
     comsat(1M), if(7), inet(7).




























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