This attack can't solves with Reverse proxies or similar. For proxies, this is just a simple WebSocket message.

So, it's hard (or can't) detect in the proxy layer or with something like Cloudflare. That's why we need a something like Sikka, which understand DDP, the protocol behind Meteor.

Anyway, only we detect bad IPs. It's a good idea to ban them from the network layer.