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Yep, thats getting towards the saturated side lol. It must be a
distributed DOS UDP flood, as I can't imagine many script kiddies
with that kind of bandwidth for a single attack spoofing 20 IPs.<br>
<br>
At that point, a lot of your CPU is just handling the incoming IP
packets. Not much to do in that situation. Even if you bonded four
GbE's together, you're still looking at needing quite a chunk of CPU
just to offload throwing away that 1Gbps.<br>
<br>
Even if you were to dynamically interact with your router to tell it
to drop the packets, your incoming bandwidth would still be
hammered. It almost has to happen at the carrier (preferably at the
carriers of the flooders) to do anything to help, and we all know
how likely that is to happen unfortunately.<br>
<br>
Good luck,<br>
<br>
<i>Boyd</i><br>
<div class="moz-signature"><br>
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<br>
On 02/23/2012 04:46 PM, NewLight Systems wrote:
<blockquote cite="mid:4F46C1B5.2060601@newlightsystems.com"
type="cite">
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The problem is that we are receiving for example 1 GBPS attacks to
one IP from serveral sources ( maybe 15 - 20 ips )<br>
<br>
That means that 1 GB of inbound is occupied. We have iptables
rules, of course, but is affecting all services on that dedicated
server<br>
<br>
El 23/02/12 23:42, Boyd G. Gafford Ph.D. escribió:
<blockquote cite="mid:4F46C0C1.60803@westportresearch.com"
type="cite">
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Hey there, thanks for responding.<br>
<br>
I'm not sure I understand what you mean by "the line is occupied
anyway." If you mean the bandwidth to the server is saturated
by the flood, then yeah, its going to affect game play.
Fortunately most servers at data centers have high enough
bandwidth to them that a typical attack doesn't saturate.<br>
<br>
If your game server port is the target of a single IP UDP flood
attack, then typically an iptables drop rule handled by the
kernel is more efficient than the game server itself, especially
if the flooded packets are server commands that are being
processed by the game server, which is sending out UDP reply
packets. That takes up much more CPU than a kernel-level packet
drop.<br>
<br>
Under those circumstances, the cheap VPS we use in Dallas has
endured 64Mbps attacks for hours and the game server is still
very playable. It would be nice if the flood was blocked at the
router or carrier level, but still iptables is pretty amazing
when the kernel drop is your last line of defense.<br>
<br>
Thanks,<br>
<br>
<i>Boyd</i><br>
<br>
<br>
On 02/23/2012 04:22 PM, NewLight Systems wrote:
<blockquote cite="mid:4F46BC41.4010505@newlightsystems.com"
type="cite">
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It's ok but this isn't working if the UDP floods to your
server because the line is occupied anyway.<br>
<br>
If you are the target, there's nothing you can do in a
dedicated server level.<br>
<br>
This type of attack ( allways if you are the target ) have to
be erradicated in a higher level ( router or carrier ) if you
want to preserve your connection<br>
<br>
El 23/02/12 23:12, Boyd G. Gafford Ph.D. escribió:
<blockquote cite="mid:4F46B9E7.2030501@westportresearch.com"
type="cite">
<meta http-equiv="content-type" content="text/html;
charset=ISO-8859-1">
Hey everyone, EscapedTurkey told me about this group, and so
I Just wanted to say a quick hello.<br>
<br>
I'm the guy who got frustrated enough with UDP flood attacks
that I wrote ServerArk to deal with the majority of them.
If anyone has any questions about the program, or any ideas
on what they would like to see in it in the future, by all
means let me know.<br>
<br>
Since I've been using it on our JA (Q3 protocol) servers (<a
moz-do-not-send="true" class="moz-txt-link-freetext"
href="http://elitewarriors.net">http://elitewarriors.net</a>)
its blocked about 20 high volume attacks (one at 64Mbps)
successfully over the past few months. As long as the
source IP of the UDP flood is not random, it works really
well.<br>
<br>
I have a few new ideas on flood detection on random IP
attacks I will ping off your guys over the next few days to
see what you think.<br>
<br>
Also kudos to whoever did the "I don't want to participate
in reflection attacks" iptables rule that matches off of the
'getstatus' UDP packet payload. If everyone who had a Q3
protocol server (COD, JA, etc) had that rule running
reflection attacks would be a LOT less potent.<br>
<br>
:)<br>
<br>
Thanks,<br>
<br>
<i>Boyd</i><br>
<br>
<div class="moz-signature"><i><font size="-1">__________________________________<br>
Boyd G. Gafford Ph.D.<br>
Manager of Software Development<br>
Westport Research Associates Inc.<br>
7001 Blue Ridge Blvd<br>
Raytown, MO 64133<br>
(816) 358-8990<br>
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<p class="p3">Dpto. Comercial y Soporte técnico</p>
<p class="p3">NewLight Systems</p>
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