[PATCH docs v5 10/10] sdn: drop global ipv6 forwarding workaround from docs

[Lukas Sichert <l.sichert@proxmox.com>]

OpenFabric and BGP fabrics with ipv6 need forwarding on transit nodes so
packets can be relayed between peers that are not directly connected.

Drop the old recommendation to enable host-wide
net.ipv6.conf.all.forwarding from the documentation. The generated
fabric interface configuration now handles the required forwarding
setup, so the manual global forwarding workaround is no longer needed.

Signed-off-by: Lukas Sichert <l.sichert@proxmox.com>
---
 pvesdn.adoc | 27 +++++++--------------------
 1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/pvesdn.adoc b/pvesdn.adoc
index c85d86a..1894270 100644
--- a/pvesdn.adoc
+++ b/pvesdn.adoc
@@ -673,23 +673,13 @@ behavior and proper source address selection throughout the fabric.
 Notes on IPv6
 ^^^^^^^^^^^^^
 
-IPv6 is currently only usable on OpenFabric fabrics. These IPv6 Fabrics need
-global IPv6 forwarding enabled on all nodes contained in the fabric. Without
-IPv6 forwarding, non-full-mesh fabrics won't work because the transit nodes
-don't forward packets to the outer nodes. Currently there isn't an easy way to
-enable IPv6 forwarding per-interface like with IPv4, so it has to be enabled
-globally. This can be accomplished by appending this line:
-
-----
-post-up sysctl -w net.ipv6.conf.all.forwarding=1
-----
-
-to a fabric interface in the `/etc/network/interfaces` file. This will enable
-IPv6 forwarding globally once that interface comes up. Note that this affects
-how your interfaces handle automatic IPv6 setup (SLAAC), Neighbour
-Advertisements, Router Solicitations, and Router Advertisements. More details
-here: https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt under
-`net.ipv6.conf.all.forwarding`.
+IPv6 is currently only usable on OpenFabric and BGP fabrics. These IPv6 Fabrics
+need IPv6 forwarding enabled on all transit nodes contained in the fabric.
+Without IPv6 forwarding, non-full-mesh fabrics won't work because the transit
+nodes don't forward packets to the outer nodes. IPv6 forwarding is enabled by
+default on the necessary interfaces using the force_forwarding flag. This flag
+is only present on kernel 6.17 or newer. More details here:
+https://docs.kernel.org/networking/ip-sysctl.html
 
 [[pvesdn_openfabric]]
 OpenFabric
@@ -715,9 +705,6 @@ all router-IDs in the fabric are contained within this prefix.
 IPv6 Prefix:: IPv6 CIDR network range (e.g., 2001:db8::/64) used to verify that
 all router-IDs in the fabric are contained within this prefix.
 
-WARNING: For IPv6 fabrics to work, global forwarding needs to be enabled on all
-nodes. Check xref:pvesdn_config_fabrics_ipv6[Notes on IPv6] for how to do it and additional info.
-
 Hello Interval:: Controls how frequently (in seconds) hello packets are sent to
 discover and maintain connections with neighboring nodes. Lower values detect
 failures faster but increase network traffic. This option is global on the
-- 
2.47.3