1.\" $NetBSD: sl.4,v 1.7 2001/09/22 16:21:42 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. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" From: @(#)lo.4 8.1 (Berkeley) 6/5/93 35.\" 36.Dd August 10, 1996 37.Dt SL 4 38.Os 39.Sh NAME 40.Nm sl 41.Nd Serial Line IP (SLIP) network interface 42.Sh SYNOPSIS 43.Cd pseudo-device sl Op Ar count 44.Sh DESCRIPTION 45The 46.Nm 47interface allows asynchronous serial lines to be used as 48.Tn IPv4 49network interfaces using the 50.Tn SLIP 51protocol. 52The 53.Nm 54interface can use Van Jacobson 55.Tn TCP 56header compression and 57.Tn ICMP 58filtering. 59.Pp 60However, 61.Tn SLIP 62can only transmit 63.Tn IPv4 64packets between preconfigured hosts on an asynchronous serial link. 65It has no provision for address negotiation, 66carriage of additional protocols (e.g. 67.Tn XNS , 68.Tn AppleTalk , 69.Tn DECNET ) , 70and is not designed for synchronous serial links. 71This is why 72.Tn SLIP 73has been superceded by the Point-to-Point Protocol 74.Pq Tn PPP , 75which does all of those things, and much more. 76.Sh DIAGNOSTICS 77.Bl -diag 78.It sl%d: af%d not supported . 79The interface was handed 80a message with addresses formatted in an unsuitable address 81family; the packet was dropped. 82.El 83.Sh SEE ALSO 84.Xr inet 4 , 85.Xr intro 4 , 86.Xr ppp 4 , 87.Xr slattach 8 , 88.Xr sliplogin 8 , 89.Xr slstats 8 90.Rs 91.%R RFC 92.%N 1055 93.%D June 1988 94.%T "A Nonstandard for Transmission of IP Datagrams over Serial Lines: SLIP" 95.Re 96.Sh HISTORY 97The 98.Nm 99device appeared in 100.Nx 1.0 . 101