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Date:      Wed, 21 Mar 2018 11:19:28 +0100
From:      "Patrick M. Hausen" <hausen@punkt.de>
To:        freebsd-stable@freebsd.org
Subject:   IPv6 connectivity lost when combining if_bridge with a VLAN ...
Message-ID:  <55A61118-8BCC-4A09-9996-9EE06CB474DA@punkt.de>

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Hi all,

a follow-up to my discovery that certain chipsets don't support =
100baseTX any more. ;-)

We use these servers as jail hosts and use if_bridge with VIMAGE and =
iocage a lot.
Our tried and true setup used to be like this:

-------------
sysctl net.link.bridge.inherit_mac=3D1
-------------
ifconfig_ixl0=3D"up"
ifconfig_ixl1=3D"up"

cloned_interfaces=3D"bridge0 bridge1"
ifconfig_bridge0_name=3D"inet0"
ifconfig_bridge1_name=3D"mgmt0"

ifconfig_inet0=3D"up addm ixl0"
ifconfig_inet0_alias0=3D"inet <address>/24"
ifconfig_inet0_ipv6=3D"inet6 <address>/64 auto_linklocal"

ifconfig_mgmt0=3D"up addm ixl1"
ifconfig_mgmt0_alias0=3D"inet <address>/16"
ifconfig_mgmt0_ipv6=3D"inet6 auto_linklocal"

defaultrouter=3D"<address>"
ipv6_defaultrouter=3D"fe80::11%inet0"
-------------

So we use link-local v6 addresses for the default gateways in every =
VLAN.
The last octet in the GW address is simply the VLAN number ...


Now, because I had to run improvised wires to a different switch before
we get to upgrading the entire rack to Gbit connectivity we tried to use
a single cable and a trunk port:

-------------
sysctl net.link.bridge.inherit_mac=3D1
-------------
ifconfig_ixl0=3D"up"

cloned_interfaces=3D"vlan7 vlan11 bridge0 bridge1"

ifconfig_vlan7=3D"up vlan 7 vlandev ixl0"
ifconfig_vlan11=3D"up vlan 11 vlandev ixl0"

ifconfig_bridge0_name=3D"inet0"
ifconfig_bridge1_name=3D"mgmt0"

ifconfig_inet0=3D"up addm vlan7"
ifconfig_inet0_alias0=3D"inet <address>/24"
ifconfig_inet0_ipv6=3D"inet6 <address>/64 auto_linklocal"

ifconfig_mgmt0=3D"up addm vlan11"
ifconfig_mgmt0_alias0=3D"inet <address>/16"
ifconfig_mgmt0_ipv6=3D"inet6 auto_linklocal"

defaultrouter=3D"<address>"
ipv6_defaultrouter=3D"fe80::11%inet0"
-------------

Nothing overly fancy in my opinion, just an orthogonal combination
of technologies. In principle this seems to work, but ...

- IPv4 connectivity comes up reliably and stays up
- external IPv6 connectivity does not come up at reboot
- I can ping6 the default GW from the machine (link-local address)
- I can ping6 other machines in the same VLAN (global unicast)
- route -6 delete default; route -6 add default fe80::11%inet0 restores =
external connectivity
- external connectivity get's lost again after a couple of hours

Only IPv6 seems to be affected, not IPv4.

Any ideas? ;-)

Thanks,
Patrick
--=20
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