Hello,

So i have one Gaming Server cs 1.6 that recently has been target of UDP 27015 port flood . when i check in Open Game Panel it says Failed Query to Server.

It happaned just few weeks ago i was not able to even restart server it said server is online but failed to responding. I tried to update steam and files and engine reHLDS still same issue. i implemented iptables to my server but still it works some time it does not.

Few Rules i have set so currently its fine but i dont know for how long.

root@mail:~# iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
DROP udp -- anywhere anywhere udp dpts:27015:27020 STRING match "f0ef8a36258af1bb64ed866538c9db76" ALGO name kmp TO 65535
LOG udp -- anywhere anywhere udp dpts:27015:27020 STRING match "f0ef8a36258af1bb64ed866538c9db76" ALGO name kmp TO 65535 LOG level warning
REJECT udp -- anywhere anywhere udp dpt:27015 #conn src/32 > 2 reject-with icmp-port-unreachable
REJECT tcp -- anywhere anywhere tcp dpt:27015 #conn src/32 > 2 reject-with icmp-port-unreachable

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination


If someone knows better rules for UDP flood then please suggest what rules can prevent them.

I have taken a tcpdump for port 27015 so please guide me the current UDP pakcket size so i can do some limit on per packet coming to my server network.

http://egcmasti.com/capture-ovh

Thanks,
egcmasti

DDOS protection cannot be accomplished on the host itself. It must be performed at the data center or carrier level.
So if your service providers don't offer DDOS mitigation, you might want to consider getting a new service provider.

- Split up your services across multiple providers and/or IP addresses.

- Proxy / VPN your services and low TTL DNS records so you can ditch the IP they're on quicker without having your server getting completely null-routed.

- Get a provider that is properly equipped to mitigate DDOS attacks; this is probably going to be quite expensive.

Please note i am using OVH Game server which has good DDOS protected for Game Server specific. Acutally you know DDOS can be bypassed in my case it might not be a exact DDOS but a flood on the port might be software level no exact idea.

Hope this might give you an idea about my server.