leath

We already have a token in the protocol and this is indeed a viable way to help drop invalid traffic. However, none of us are really experienced enough with the networking stack of the linux kernel (nor are these things very well documented) to craft a conntrack module or an XDP program to parse the header and keep track of the assigned tokens. Dropping these any later than the nftables stage is just not enough as we already do that.

We have a small team who work on this project during our free times and most of us just don’t currently have the time to dig into conntrack/nftables/xdp.

A mention in a German gaming magazine very early on in the games lifetime brought a fair bit of attention

The public prosecutor did. Not sure how much more intimidating we could be than a prosecutor showing up threatening legal action

Funnily enough our experience has been much the reverse. Hetzner will let us use the 1g dedicated link they promise however we want. Most other hosters will put blanket filters that are too broad or their smart ddos filtering will kick in, which it turns out is not smart enough to learn an arbitrary protocol :)

OVH has consistently been filtering legitimate traffic for us each time we tried them and we’ve tried almost every tier of service they offer.

100% agree with you. We gave the ISPs more than enough time to get this under control, yet they don't seem to want to bear any cost in preventing what are essentially crimes (though as shown in the blog post cybercrimes are seen as a bit of a joke unless they cause monetary damages) taking place on their networks. If they are not willing to self-regulate it's the governments job to regulate them.

The blog post does mention this possibility. In a similar vein we can also try to mimic a protocol that is well supported by hosters, like source or minecraft but I'm fairly certain that would be the single most ugliest piece of code ever written :)

Documentation seems to say that they let you use the network from any platform as long as you have a Steam release. The bigger concern is that this requires linking with a closed source library, which means the open source version of the client could no longer connect to our servers without linking to a closed source blob.

That is sort of a non starter for us without some workaround like maybe hosting our own relays for the open source clients.

The proof of work idea is cute, but at this stage it's not necessary as profiling seems to show attacks don't get too deep into the netcode before getting dropped. It's hard to know without testing but I'm fairly certain any kind of PoW would cost more to check. This reminds me of a blogpost that is at least fun to read: http://ithare.com/udp-for-games-security-encryption-and-ddos...

Regarding the HTTPS request thing, we already did this for an event and I'm currently getting it set up on all servers. The blog post forgot to mention this one :)

This is a nice read https://blog.cloudflare.com/the-root-cause-of-large-ddos-ip-...

It is indeed possible for ISPs to stop this, but my guess is that it's cheaper not to :) Large ISPs could require egress filtering for peering with them.

As the blogpost mentions TCP is not exactly desirable for our project. Moreover, if you contact Cloudflare about those products you'll get a monthly quote that is far beyond what an open source project run by donations can sustain :)

We've had several servers with OVH, including their kimisufi line, So You Start GAME line, their standard GAME line and their standard servers. While I'm sure these are great for common games their DDoS protection seems to get confused by our very non-standard protocol, ending up blocking most if not all traffic from non-connected players.

Actually not all port 53 as there are some DNS servers still accessible and actually resolves stuff fine.