EvilZone

Hacking and Security => Hacking and Security => Topic started by: DataFlow on February 11, 2013, 05:50:48 PM

Title: Defend against ddos attacks
Post by: DataFlow on February 11, 2013, 05:50:48 PM
What its the best way to defend against ddos attacks?
Title: Re: Defend against ddos attacks
Post by: proxx on February 11, 2013, 07:47:41 PM
Depends what kind of attack, whats it targetted at and what OS you use.
Please give more details.
Title: Re: Defend against ddos attacks
Post by: DataFlow on February 11, 2013, 08:23:11 PM
Linux.

Its a private game server.

and we are being ddosed at rate 10 GBit/s
Title: Re: Defend against ddos attacks
Post by: ande on February 11, 2013, 09:02:02 PM
Like proxx said, still depends on what kind of attack. A UDP flood or SYN flood(any type of flood that does not require or use an established connection) will be 10GBit/s no matter what you do at your end. In this case you will have to contact the hosting provider and ask them to block it at a higher level so that the traffic never reaches your server.

However, many flood types are only effective because of poorly written services that will just accept tons and tons of gibberish data without severing the connection. In this case, just add the IP address of the flooder to iptables or if on windows, whatever firewall policy you are using.
Title: Re: Defend against ddos attacks
Post by: proxx on February 11, 2013, 10:07:12 PM
You could try to drop the packets with iptables.
Use drop and do not actively block the packets.
But as stated thats a lot of traffic.

Blocking the IP's is possible however not always practical.
You basically dont want to generate CPU cycles.

What kind of traffic are you receiving?
Title: Re: Defend against ddos attacks
Post by: Stackprotector on February 12, 2013, 10:16:43 PM
You might consider blocking everything and only allowing some ip's (as i assume it is a PRIVATE server)
Title: Re: Defend against ddos attacks
Post by: WirelessDesert on February 12, 2013, 10:39:06 PM
You might consider blocking everything and only allowing some ip's (as i assume it is a PRIVATE server)
Just a question: Wouldn't blocking IP's just generate more problem then doing something else, since then you(the server) have to check if the ip is blocked, and then ignore to send any packets to it!??
Title: Re: Defend against ddos attacks
Post by: ande on February 12, 2013, 11:53:28 PM
Just a question: Wouldn't blocking IP's just generate more problem then doing something else, since then you(the server) have to check if the ip is blocked, and then ignore to send any packets to it!??

You are most certainly right. But the alternative is much worse; Your services taking all the traffic and being unresponsive. Unless its a flood not targeting services ofc. In which case, there is no point in blocking it if the server is still more or less responding.

With that being said, iptables(assuming you are using linux) has a pretty decent performance. The DoS needs to be pretty hardcore and the filter list pretty huge before any performance issues arise.


EDIT: This is also another reason to contact the hosters and ask them to block IP's before they ever reach you.
Title: Re: Defend against ddos attacks
Post by: iTpHo3NiX on February 13, 2013, 06:38:13 AM
CloudFlare
Title: Re: Defend against ddos attacks
Post by: Stackprotector on February 13, 2013, 07:29:11 AM
CloudFlare
In don't think a premium cloud DNC would help a private gaming server. Serverside solutions or isp solutions. Or buy some extra hardware.
Title: Re: Defend against ddos attacks
Post by: h4xx0r on February 13, 2013, 08:58:54 AM
In don't think a premium cloud DNC would help a private gaming server. Serverside solutions or isp solutions. Or buy some extra hardware.


Cloudflare won't provide protection for your gaming servers.
Like the guy said above, you need to contact the datacenter and ask them to block the intruder IP at a level higher than you have access to so the DDoS doesn't even reach the DC.