network-bridge.sh

sudo su -

$endpoint=$(curl -s http://metadata.google.internal/computeMetadata/v1/instance/attributes/FORWARD_IPADDRESS -H "Metadata-Flavor: Google")

if [ -x /bin/firewall-cmd ]
then
   sysctl -w net.ipv4.ip_forward=1
   firewall-cmd --permanent --add-masquerade
   firewall-cmd --permanent --add-forward-port=port=443:proto=tcp:toaddr=$endpoint
else
   sysctl -w net.ipv4.ip_forward=1
   iptables -t nat -A POSTROUTING -j MASQUERADE
   iptables -t nat -A PREROUTING -p tcp --dport 443 -j DNAT --to-destination $endpoint
fi

sysctl -ew net.netfilter.nf_conntrack_buckets=1048576
sysctl -ew net.netfilter.nf_conntrack_max=8388608

exit 0