| gre.4 (163500) | gre.4 (179894) |
|---|---|
| 1.\" $NetBSD: gre.4,v 1.28 2002/06/10 02:49:35 itojun Exp $ 2.\" 3.\" Copyright 1998 (c) The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Heiko W.Rupp <hwr@pilhuhn.de> 8.\" --- 20 unchanged lines hidden (view full) --- 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" | 1.\" $NetBSD: gre.4,v 1.28 2002/06/10 02:49:35 itojun Exp $ 2.\" 3.\" Copyright 1998 (c) The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Heiko W.Rupp <hwr@pilhuhn.de> 8.\" --- 20 unchanged lines hidden (view full) --- 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" |
| 37.\" $FreeBSD: head/share/man/man4/gre.4 163500 2006-10-19 07:41:47Z danger $ | 37.\" $FreeBSD: head/share/man/man4/gre.4 179894 2008-06-20 17:26:34Z thompsa $ |
| 38.\" | 38.\" |
| 39.Dd June 9, 2002 | 39.Dd June 20, 2008 |
| 40.Dt GRE 4 41.Os 42.Sh NAME 43.Nm gre 44.Nd encapsulating network device 45.Sh SYNOPSIS 46To compile the 47.Ns Nm --- 114 unchanged lines hidden (view full) --- 162The 163.Cm link1 164flag is not used to choose encapsulation, but to modify the 165internal route search for the remote tunnel endpoint, see the 166.Sx BUGS 167section below. 168.It Dv GREGPROTO 169Query operation mode. | 40.Dt GRE 4 41.Os 42.Sh NAME 43.Nm gre 44.Nd encapsulating network device 45.Sh SYNOPSIS 46To compile the 47.Ns Nm --- 114 unchanged lines hidden (view full) --- 162The 163.Cm link1 164flag is not used to choose encapsulation, but to modify the 165internal route search for the remote tunnel endpoint, see the 166.Sx BUGS 167section below. 168.It Dv GREGPROTO 169Query operation mode. |
| 170.It Dv GRESKEY 171Set the GRE key used for outgoing packets. 172A value of 0 disables the key option. 173.It Dv GREGKEY 174Get the GRE key currently used for outgoing packets. 1750 means no outgoing key. |
|
| 170.El 171.Pp 172Note that the IP addresses of the tunnel endpoints may be the same as the 173ones defined with 174.Xr ifconfig 8 175for the interface (as if IP is encapsulated), but need not be, as e.g.\& when 176encapsulating AppleTalk. 177.Sh EXAMPLES --- 81 unchanged lines hidden (view full) --- 259.Cm link1 260flag (as discussed in the 261.Sx BUGS 262section below) may (and probably should) be set. 263.Sh NOTES 264The MTU of 265.Nm 266interfaces is set to 1476 by default, to match the value used by Cisco routers. | 176.El 177.Pp 178Note that the IP addresses of the tunnel endpoints may be the same as the 179ones defined with 180.Xr ifconfig 8 181for the interface (as if IP is encapsulated), but need not be, as e.g.\& when 182encapsulating AppleTalk. 183.Sh EXAMPLES --- 81 unchanged lines hidden (view full) --- 265.Cm link1 266flag (as discussed in the 267.Sx BUGS 268section below) may (and probably should) be set. 269.Sh NOTES 270The MTU of 271.Nm 272interfaces is set to 1476 by default, to match the value used by Cisco routers. |
| 273If grekey is set this is lowered to 1472. |
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| 267This may not be an optimal value, depending on the link between the two tunnel 268endpoints. 269It can be adjusted via 270.Xr ifconfig 8 . 271.Pp 272For correct operation, the 273.Nm 274device needs a route to the destination that is less specific than the --- 52 unchanged lines hidden (view full) --- 327.Xr ifconfig 8 328command line. 329This implies that the GRE packet destination and the ifconfig remote host 330are not the same IP addresses, and that the GRE destination does not route 331over the 332.Nm 333interface itself. 334.Pp | 274This may not be an optimal value, depending on the link between the two tunnel 275endpoints. 276It can be adjusted via 277.Xr ifconfig 8 . 278.Pp 279For correct operation, the 280.Nm 281device needs a route to the destination that is less specific than the --- 52 unchanged lines hidden (view full) --- 334.Xr ifconfig 8 335command line. 336This implies that the GRE packet destination and the ifconfig remote host 337are not the same IP addresses, and that the GRE destination does not route 338over the 339.Nm 340interface itself. 341.Pp |
| 335The GRE RFCs are not yet fully implemented (no GRE options). | 342The current implementation uses the key only for outgoing packets. 343Incomming packets with a different key or without a key will be treated as if they 344would belong to this interface. 345.Pp 346RFC1701 is not fully supported, however all unsupported features have been 347deprecated in RFC2784. |