IPv6 connectivity lost when combining if_bridge with a VLAN ...

[Patrick M. Hausen]

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=1
-------------
ifconfig_ixl0="up"
ifconfig_ixl1="up"

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

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

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

defaultrouter="<address>"
ipv6_defaultrouter="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=1
-------------
ifconfig_ixl0="up"

cloned_interfaces="vlan7 vlan11 bridge0 bridge1"

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

ifconfig_bridge0_name="inet0"
ifconfig_bridge1_name="mgmt0"

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

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

defaultrouter="<address>"
ipv6_defaultrouter="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
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