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[src/trunk]: src/share/man/man4 Bump date for previous. Remove trailing white...
details: https://anonhg.NetBSD.org/src/rev/bd99d8c2c21a
branches: trunk
changeset: 579892:bd99d8c2c21a
user: wiz <wiz%NetBSD.org@localhost>
date: Wed Mar 30 18:53:33 2005 +0000
description:
Bump date for previous. Remove trailing whitespace.
New sentence, new line. Fix some macro usage.
diffstat:
share/man/man4/gre.4 | 86 +++++++++++++++++++++++++++++----------------------
1 files changed, 48 insertions(+), 38 deletions(-)
diffs (187 lines):
diff -r 1fd2bce71ce2 -r bd99d8c2c21a share/man/man4/gre.4
--- a/share/man/man4/gre.4 Wed Mar 30 18:42:22 2005 +0000
+++ b/share/man/man4/gre.4 Wed Mar 30 18:53:33 2005 +0000
@@ -1,4 +1,4 @@
-.\" $NetBSD: gre.4,v 1.30 2005/03/30 17:19:52 is Exp $
+.\" $NetBSD: gre.4,v 1.31 2005/03/30 18:53:33 wiz Exp $
.\"
.\" Copyright 1998 (c) The NetBSD Foundation, Inc.
.\" All rights reserved.
@@ -34,7 +34,7 @@
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
-.Dd June 9, 2002
+.Dd March 30, 2005
.Dt GRE 4
.Os
.Sh NAME
@@ -46,7 +46,8 @@
The
.Nm gre
network interface pseudo device encapsulates datagrams
-into IP. These encapsulated datagrams are routed to a destination host,
+into IP.
+These encapsulated datagrams are routed to a destination host,
where they are decapsulated and further routed to their final destination.
The
.Dq tunnel
@@ -64,17 +65,19 @@
.Bl -tag -width abc
.It GRE encapsulation (IP protocol number 47)
Encapsulated datagrams are
-prepended an outer datagram and a GRE header. The GRE header specifies
-the type of the encapsulated datagram and thus allows for tunneling other
-protocols than IP like e.g. AppleTalk. GRE mode is also the default tunnel
-mode on Cisco routers. This is also the default mode of operation of the
+prepended an outer datagram and a GRE header.
+The GRE header specifies the type of the encapsulated datagram and
+thus allows for tunneling other protocols than IP like e.g. AppleTalk.
+GRE mode is also the default tunnel mode on Cisco routers.
+This is also the default mode of operation of the
.Sy gre Ns Ar X
interfaces.
.It MOBILE encapsulation (IP protocol number 55)
Datagrams are
-encapsulated into IP, but with a shorter encapsulation. The original
-IP header is modified and the modifications are inserted between the
-so modified header and the original payload. Like
+encapsulated into IP, but with a shorter encapsulation.
+The original IP header is modified and the modifications are inserted
+between the so modified header and the original payload.
+Like
.Xr gif 4 ,
only for IP in IP encapsulation.
.El
@@ -86,26 +89,26 @@
such as:
.Bl -tag -width aaa
.It GRESADDRS :
-Set the IP address of the local tunnel end. This is the source address
-set by or displayed by ifconfig for the
+Set the IP address of the local tunnel end.
+This is the source address set by or displayed by ifconfig for the
.Sy gre Ns Ar X
interface.
.It GRESADDRD :
-Set the IP address of the remote tunnel end. This is the destination address
-set by or displayed by ifconfig for the
+Set the IP address of the remote tunnel end.
+This is the destination address set by or displayed by ifconfig for the
.Sy gre Ns Ar X
interface.
.It GREGADDRS :
-Query the IP address that is set for the local tunnel end. This is the
-address the encapsulation header carries as local address (i.e. the real
-address of the tunnel start point.)
+Query the IP address that is set for the local tunnel end.
+This is the address the encapsulation header carries as local
+address (i.e. the real address of the tunnel start point.)
.It GREGADDRD :
-Query the IP address that is set for the remote tunnel end. This is the
-address the encapsulated packets are sent to (i.e. the real address of
-the remote tunnel endpoint.)
+Query the IP address that is set for the remote tunnel end.
+This is the address the encapsulated packets are sent to (i.e. the
+real address of the remote tunnel endpoint.)
.It GRESPROTO :
-Set the operation mode to the specified IP protocol value. The
-protocol is passed to the interface in (struct ifreq)-\*[Gt]ifr_flags.
+Set the operation mode to the specified IP protocol value.
+The protocol is passed to the interface in (struct ifreq)-\*[Gt]ifr_flags.
The operation mode can also be given as
.Bl -tag -width link0xxx
.It link0
@@ -139,7 +142,7 @@
+------Host B----------Host C----------+
.Ed
On host A
-.Ns ( Nx ) :
+.Pq Nx :
.Bd -literal
# route add default B
# ifconfig greN create
@@ -159,7 +162,7 @@
.Ed
OR
On Host D
-.Ns ( Nx ) :
+.Pq Nx :
.Bd -literal
# route add default C
# ifconfig greN create
@@ -211,7 +214,7 @@
.Sx BUGS
section below) may (and probably should) be set.
.Pp
-Along these lines, you can use GRE tunnels to interconnect two IPv6
+Along these lines, you can use GRE tunnels to interconnect two IPv6
networks over an IPv4 infrastructure, or to hook up to the IPv6 internet
via an IPv4 tunnel to a Cisco router.
.Bd -literal
@@ -221,19 +224,25 @@
+----- the Internet ------+
.Ed
-The example will use the following addressing: NetBSD A has the
+The example will use the following addressing:
+.Nx
+A has the
IPv4 address A and the IPv6 address 2001:db8:1::1 (connects to internal
-network 2001:db8:1::/64). Cisco B has external IPv4 address B. All
-the IPv6 internet world is behind B, so A wants to route 0::0/0 (the IPv6
-default route) into the tunnel. The GRE tunnel will use a transit
-network: 2001:db8:ffff::1/64 on the NetBSD side, and ::2/64 on the Cisco
-side.
+network 2001:db8:1::/64).
+Cisco B has external IPv4 address B.
+All the IPv6 internet world is behind B, so A wants to route 0::0/0
+(the IPv6 default route) into the tunnel.
+The GRE tunnel will use a transit network: 2001:db8:ffff::1/64 on
+the
+,Nx
+side, and ::2/64 on the Cisco side.
Then the following commands will configure the tunnel:
.Pp
-On router A (NetBSD):
+On router A
+.Pq Nx :
.Bd -literal
# ifconfig greN create
- # ifconfig greN inet6 2001:db8:ffff::1/64
+ # ifconfig greN inet6 2001:db8:ffff::1/64
# ifconfig greN tunnel A B
# route add -inet6 2001:db8:ffff::/64 2001:db8:ffff::2 -ifp greN
# route add -inet6 0::0/0 2001:db8:ffff::2 -ifp greN
@@ -257,7 +266,8 @@
.Sy gre Ns Ar X
interfaces is set to 1476 by default to match the value used by Cisco routers.
This may not be an optimal value, depending on the link between the two tunnel
-endpoints. It can be adjusted via
+endpoints.
+It can be adjusted via
.Xr ifconfig 8 .
.Pp
For correct operation, the
@@ -265,8 +275,8 @@
device needs a route to the destination that is less specific than the
one over the tunnel.
(Basically, there needs to be a route to the decapsulating host that
-does not run over the tunnel, as this would be a loop. This is not
-relevant for IPv6-over-IPv4 tunnels, of course.)
+does not run over the tunnel, as this would be a loop.
+This is not relevant for IPv6-over-IPv4 tunnels, of course.)
If the addresses are ambiguous, doing the
.Xr ifconfig 8
.Li tunnel
@@ -305,8 +315,8 @@
.Sh BUGS
The compute_route() code in if_gre.c toggles the last bit of the
IP-address to provoke the search for a less specific route than the
-one directly over the tunnel to prevent loops. This is possibly not
-the best solution.
+one directly over the tunnel to prevent loops.
+This is possibly not the best solution.
.Pp
To avoid the address munging described above, turn on the link1 flag
on the
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