BSD 4_4 development

[unix-history] / usr / share / man / cat4 / lo.0

LO(4)                       BSD Programmer's Manual                      LO(4)

N\bNA\bAM\bME\bE
    l\blo\bo - software loopback network interface

S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS
    p\bps\bse\beu\bud\bdo\bo-\b-d\bde\bev\bvi\bic\bce\be
    l\blo\boo\bop\bp

D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN
    The l\blo\boo\bop\bp 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 _\bn_\be_\bv_\be_\br be configured first unless no hardware interfaces
    exist.

D\bDI\bIA\bAG\bGN\bNO\bOS\bST\bTI\bIC\bCS\bS
    l\blo\bo%\b%d\bd:\b: c\bca\ban\bn'\b't\bt h\bha\ban\bnd\bdl\ble\be a\baf\bf%\b%d\bd.\b.  The interface was handed a message with ad-
    dresses formatted in an unsuitable address family; the packet was
    dropped.

S\bSE\bEE\bE A\bAL\bLS\bSO\bO
    intro(4),  inet(4),  ns(4)

H\bHI\bIS\bST\bTO\bOR\bRY\bY
    The l\blo\bo device appeared in 4.2BSD.

B\bBU\bUG\bGS\bS
    Previous versions of the system enabled the loopback interface automati-
    cally, 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.

4.2 Berkeley Distribution        June 5, 1993                                1