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authorjmc <jmc@openbsd.org>2018-02-23 09:50:30 +0000
committerjmc <jmc@openbsd.org>2018-02-23 09:50:30 +0000
commit020a2fff9ba31290030fbdfaff58d9beb78b60a0 (patch)
tree55a539c3b5108cfaa66bb219c29e2ee273a1b888
parentsome cleanup for BindInterface and ssh-keyscan; (diff)
downloadwireguard-openbsd-020a2fff9ba31290030fbdfaff58d9beb78b60a0.tar.xz
wireguard-openbsd-020a2fff9ba31290030fbdfaff58d9beb78b60a0.zip
various tweaks; ok dlg
-rw-r--r--share/man/man4/gre.443
1 files changed, 21 insertions, 22 deletions
diff --git a/share/man/man4/gre.4 b/share/man/man4/gre.4
index a3973e2e313..43d42192622 100644
--- a/share/man/man4/gre.4
+++ b/share/man/man4/gre.4
@@ -1,4 +1,4 @@
-.\" $OpenBSD: gre.4,v 1.65 2018/02/23 03:03:36 dlg Exp $
+.\" $OpenBSD: gre.4,v 1.66 2018/02/23 09:50:30 jmc Exp $
.\" $NetBSD: gre.4,v 1.10 1999/12/22 14:55:49 kleink Exp $
.\"
.\" Copyright 1998 (c) The NetBSD Foundation, Inc.
@@ -145,7 +145,7 @@ By default the MTU of an
.Nm nvgre
interface is set to 1500, and the Don't Fragment flag is set.
The MTU on the network interfaces carrying underlay network traffic
-must be raised to accomodate this and the overhead of the NVGRE
+must be raised to accommodate this and the overhead of the NVGRE
encapsulation, or the
.Nm nvgre
interface must be reconfigured for less capable underlays.
@@ -312,9 +312,27 @@ Remove the configuration of the interface used for multicast
communication.
.\" bridge(4) ioctls should go here too.
.El
+.Ss Security Considerations
+The GRE protocol in all its flavours does not provide any integrated
+security features.
+GRE should only be deployed on trusted private networks,
+or protected with IPsec to add authentication and encryption for
+confidentiality.
+IPsec is especially recommended when transporting GRE over the
+public internet.
+.Pp
+The Packet Filter
+.Xr pf 4
+can be used to filter tunnel traffic with endpoint policies
+.Xr pf.conf 5 .
+.Pp
+The Time-to-Live (TTL) value of a tunnel can be set to 1 or a low
+value to restrict the traffic to the local network:
+.Bd -literal -offset indent
+# ifconfig gre0 tunnelttl 1
+.Ed
.Sh EXAMPLES
.Ss Point-to-Point Layer 3 GRE tunnel interfaces (gre)
-.Nm gre
Configuration example:
.Bd -literal
Host X ---- Host A ------------ tunnel ------------ Cisco D ---- Host E
@@ -637,22 +655,3 @@ the configuration of child
interfaces or the bridging of VLAN tagged traffic across the tunnel.
These non-restrictions allow non-compliant tunnels to be configured
which may not interoperate with other vendors.
-.Sh SECURITY CONSIDERATIONS
-The GRE protocol in all its flavours does not provide any integrated
-security features.
-GRE should only be deployed on trusted private networks,
-or protected with IPsec to add authentication and encryption for
-confidentiality.
-IPsec is especially recommended when transporting GRE over the
-public internet.
-.Pp
-The Packet Filter
-.Xr pf 4
-can be used to filter tunnel traffic with endpoint policies
-.Xr pf.conf 5 .
-.Pp
-The Time-to-Live (TTL) value of a tunnel can be set to 1 or a low
-value to restrict the traffic to the local network:
-.Bd -literal -offset indent
-# ifconfig gre0 tunnelttl 1
-.Ed