Layers of OVH Network
Here is my configurations
If you are using the OVH dedicated servers. You have an extra GAME firewall can be use. It is important to UDP based games. Please refer to https://docs.ovh.com/gb/en/dedicated/firewall-network/#configuring-armor
Due to a bug of OVH Firewall, you still need to block malformed ACK connections by using iptables:
Block all incoming connections, only open the port that necessary.