1.\" $NetBSD: sl.4,v 1.10 2004/12/05 13:27:26 wiz Exp $ 2.\" 3.\" Copyright (c) 1983, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" From: @(#)lo.4 8.1 (Berkeley) 6/5/93 31.\" 32.Dd December 5, 2004 33.Dt SL 4 34.Os 35.Sh NAME 36.Nm sl 37.Nd Serial Line IP (SLIP) network interface 38.Sh SYNOPSIS 39.Cd pseudo-device sl 40.Sh DESCRIPTION 41The 42.Nm 43interface allows asynchronous serial lines to be used as 44.Tn IPv4 45network interfaces using the 46.Tn SLIP 47protocol. 48The 49.Nm 50interface can use Van Jacobson 51.Tn TCP 52header compression and 53.Tn ICMP 54filtering. 55.Pp 56However, 57.Tn SLIP 58can only transmit 59.Tn IPv4 60packets between preconfigured hosts on an asynchronous serial link. 61It has no provision for address negotiation, 62carriage of additional protocols (e.g. 63.Tn XNS , 64.Tn AppleTalk , 65.Tn DECNET ) , 66and is not designed for synchronous serial links. 67This is why 68.Tn SLIP 69has been superceded by the Point-to-Point Protocol 70.Pq Tn PPP , 71which does all of those things, and much more. 72.Sh DIAGNOSTICS 73.Bl -diag 74.It sl%d: af%d not supported . 75The interface was handed 76a message with addresses formatted in an unsuitable address 77family; the packet was dropped. 78.El 79.Sh SEE ALSO 80.Xr inet 4 , 81.Xr intro 4 , 82.Xr ppp 4 , 83.Xr slattach 8 , 84.Xr sliplogin 8 , 85.Xr slstats 8 86.Rs 87.%R RFC 88.%N 1055 89.%D June 1988 90.%T "A Nonstandard for Transmission of IP Datagrams over Serial Lines: SLIP" 91.Re 92.Sh HISTORY 93The 94.Nm 95device appeared in 96.Nx 1.0 . 97