Gabriel's upstream kernel patch [1] added net.ipv6.conf.<iface>.force_forwarding. This allows enabling IPv6 forwarding on selected interfaces without requiring net.ipv6.conf.all.forwarding.
This is useful for SDN setups because all.forwarding has host-wide side effects. In particular, it disables Router Advertisement processing by default, which can break SLAAC on unrelated interfaces. SDN only needs forwarding on the VNet, exit-node, or fabric interfaces that participate in routed IPv6 traffic. This series generates ifupdown post-up/post-down commands for those interfaces so force_forwarding is enabled when the interface is brought up and reset when it is brought down. The tests are adjusted for the generated /etc/network/interfaces.d/sdn output. Also the series rewrites the documenation to reflect the updated behaviour. [1] lkml.org/lkml/2025/7/7/577 changes from v1 to v2 (thanks @Gabriel, @Hannes): -add force_fowarding also to bgp fabrics -explictly mention the force_forwarding flag in the documenation -add a reference link to the sysctl documentation -mention bgp as a fabric with ipv6 support network: Lukas Sichert (2): sdn: evpn: enable force_forwarding for ipv6 forwarding to subnets sdn: simple: enable force_forwarding for ipv6 forwarding to subnets src/PVE/Network/SDN/Zones/EvpnPlugin.pm | 20 +++++++++++++++---- src/PVE/Network/SDN/Zones/SimplePlugin.pm | 20 +++++++++++++++---- .../expected_sdn_interfaces | 4 ++++ .../exitnode_snat/expected_sdn_interfaces | 4 ++++ .../exitnodenullroute/expected_sdn_interfaces | 4 ++++ .../evpn/ipv4ipv6/expected_sdn_interfaces | 4 ++++ .../zones/evpn/ipv6/expected_sdn_interfaces | 4 ++++ .../evpn/ipv6underlay/expected_sdn_interfaces | 4 ++++ .../simple/ipv4v6/expected_sdn_interfaces | 4 ++++ .../simple/ipv6snat/expected_sdn_interfaces | 4 ++++ 10 files changed, 64 insertions(+), 8 deletions(-) perl-rs: Lukas Sichert (2): fabrics: openfabric: enable force_forwarding for ipv6 transit traffic fabrics: bgp: enable force_forwardgin for ipv6 transit traffic pve-rs/src/bindings/sdn/fabrics.rs | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) docs: Lukas Sichert (1): sdn: drop global iv6 forwarding workaround from OpenFabric docs pvesdn.adoc | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-) Summary over all repositories: 12 files changed, 87 insertions(+), 24 deletions(-) -- Generated by murpp 0.12.0
