1.\" $FreeBSD: src/usr.sbin/gifconfig/gifconfig.8,v 1.1.2.11 2003/03/11 21:13:49 trhodes Exp $ 2.\" $KAME: gifconfig.8,v 1.6 2000/11/22 11:10:09 itojun Exp $ 3.\" 4.\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the project nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.Dd May 17, 1998 32.Dt GIFCONFIG 8 33.Os 34.Sh NAME 35.Nm gifconfig 36.Nd configure generic IP tunnel 37.\" 38.Sh SYNOPSIS 39.Nm 40.Ar interface 41.Op Ar af 42.Op Ar physsrc physdest 43.Nm 44.Ar interface 45.Ic delete 46.Nm 47.Fl a 48.Sh DESCRIPTION 49The 50.Nm 51utility configures the physical address for the generic IP tunnel 52interface, such as "gif0". 53Argument 54.Ar physsrc 55and 56.Ar physdest 57are interpreted as the outer source/destination address for 58encapsulating IPv4/v6 header. 59Argument 60.Ar af 61specifies the address family for 62.Ar physsrc 63and 64.Ar physdest . 65.Ar af 66can be 67.Li inet 68or 69.Li inet6 , 70and will be treated as 71.Li inet 72if ommitted. 73.Pp 74If a special argument 75.Ic delete 76is specified, 77.Nm 78just deletes the existing source and destination addresses on 79.Ar interface . 80If no outer addresses are specified, this usage has no effect. 81.Pp 82The 83.Nm 84utility takes the following optional argument: 85.Bl -tag -width Ds 86.It Fl a 87Display information associated with all 88.Xr gif 4 89interfaces. 90.El 91.Pp 92Please note that it is very easy to create infinite routing loop, 93when you configure tunnel over same address family 94(e.g. IPv4-over-IPv4). 95.Pp 96Each 97.Xr gif 4 98interface is created at runtime using interface cloning. 99This is 100most easily done with the 101.Xr ifconfig 8 102.Cm create 103command or using the 104.Va gifconfig_ Ns Aq Ar interface 105variable in 106.Xr rc.conf 5 . 107.Sh EXAMPLES 108If you would like to configure IPv6 over IPv4 109(aka IPv6 in IPv4) 110tunnel between 111.Li 10.1.1.1 112and 113.Li 10.2.3.4 , 114you should perform the following command: 115.Bd -literal -offset 116# gifconfig gif0 inet 10.1.1.1 10.2.3.4 117.Ed 118.Pp 119.\" To use the 120.\" .Li 0.0.0.0 121.\" feature to establish a tunnel from host1 to host3 122.\" which will encapsulate and carry packets from host2, on host1 do: 123.\" .Bd -literal -offset 124.\" # ifconfig gif0 inet host1 127.0.0.2 # assign an address to gif0 125.\" # gifconfig gif0 inet host1 0.0.0.0 # assign encapsulation addresses 126.\" # route add host2 host3 -ifp gif0: # encap host2 packets, send to host3 127.\" .Ed 128.\" .Pp 129.\" Note: the 130.\" .Fl ifp 131.\" option to route does not work as documented in 132.\" most versions of FreeBSD. 133.\" .Pp 134.\" On host3 do: 135.\" .Bd -literal -offset 136.\" # ifconfig gif0 inet host3 127.0.0.2 # assign an address to gif0 137.\" # gifconfig gif0 inet host3 0.0.0.0 # assign encapsulation addresses 138.\" .Ed 139.\" .Pp 140.\" Now if you ping host2 from host1, the packets should be encapsulated 141.\" with outer source address = host1 and outer destination address = host3, 142.\" and delivered to host3. 143.\" host3 will decapsulate the packet and deliver it normally to host2. 144.\" .Pp 145This is also possible to use IPv6 as outer proto, by replacing 146.Li inet 147to 148.Li inet6 , 149and IPv4 addresses to some appropriate IPv6 addresses in above example. 150.Sh RETURN VALUES 151The command exits with exit status of 1 on errors, 0 on success. 152.Sh SEE ALSO 153.Xr gif 4 , 154.Xr ifconfig 8 155.Sh HISTORY 156The 157.Nm 158utility first appeared in WIDE Hydrangea IPv6 protocol stack kit. 159.Pp 160IPv6 and IPsec support based on the KAME Project (http://www.kame.net/) stack 161was initially integrated into 162.Fx 4.0 163