A Lot of DDoS Attacks. How to Prevent?

Lately, Theres been a lot of DDoS attacks on this one server which i administrate. I’m trying to look for a way to prevent the DDoS, That’s free of charge.
Is there anyway to prevent it/ Stop the current user permanently?
I believe it’s one person, because they threatened to ddos the server before, Later they get banned, Then bam the attacks come in.

So anyway to stop it for free of charge? And i say free of charge,cause the server provoiders charge 50 dollars for protection to ddos attacks.

Most likely it’s a DoS not a DDoS so just install the srcds engine plugin to prevent it. http://www.sourceop.com/modules.php?name=Downloads&d_op=viewdownload&cid=9

Ah, yeah dos would be the one and not ddos.

I’ll give it a shot, Thanks.

That only patches a source exploit of which very few people use these days.

My server is getting hit by this attack every night. Someone is flooding a lot of UDP packets with length 28 from about 500 different IP addresses. As I am running on Windows 2008 R2 and not Linux, I cannot use iptables to block packets based on length. My DC also doesn’t offer the option of a hardware firewall or DOS protection.

Either this vulnerability needs fixing, or there needs to be a viable Windows alternative to the “iptables” rule.