nanog mailing list archives

Re: UDP port 80 DDoS attack


From: Keegan Holley <keegan.holley () sungard com>
Date: Sun, 5 Feb 2012 22:30:20 -0500

2012/2/5 Steve Bertrand <steve.bertrand () gmail com>

On 2012.02.05 20:37, Keegan Holley wrote:

2012/2/5 Dobbins, Roland<rdobbins () arbor net>


 S/RTBH - as opposed to D/RTBH - doesn't kill the patient.  Again, suggest
you read the preso.


Source RTBH often falls victim to rapidly changing or spoofed source IP"s.
It also isn't as widely supported as it should be. I never said DDOS was
hopeless, there just aren't a wealth of defenses against it.


This is so very easily automated. Even if you don't actually want to
trigger the routes automatically, finding the sources you want to blackhole
is as simple as a monitor port, tcpdump and some basic Perl.


This is still vulnerable to spoofing which could cause you to filter
legitimate traffic and make the problem worse.  Not saying that S/RTBH is a
bad idea.  RTBH is effective and a great idea just not very elegant.



...and as far as this not having been deployed in many ISPs (per your next
message)... their mitigation strategies should be asked up front, and if
they don't have any (or don't know what you speak of), find a new ISP.


You sometimes have to weigh the pro's and cons.  You can't always pick the
guys with the coolest knobs.


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