Sysctl

Disable rp_filter

for i in /proc/sys/net/ipv4/conf/*/rp_filter; do
	echo 0 > $i
done

Additional notes

http://unix.stackexchange.com/questions/90443/sysctl-proc-sys-net-ipv46-conf-whats-the-difference-between-all-defau
https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt

Ensure VLAN packets originate from the correct VLAN interface in iptables

net.bridge.bridge-nf-filter-vlan-tagged = 1
net.bridge.bridge-nf-pass-vlan-input-dev = 1