No, I did not get a tcpdump.  My hosting provider notified me of the abuse but 
they already had it stopped. I did get the ip address of the receiving end, and 
it was my ip address, port 123 to server x port 80, udp. I'm going to add a 
rate limit to iptables, and locking it down to port 123 and 1024-65535.  I 
wished it was as simple as to only allow udp/123 source and destination, but I 
get so many people behind natted connections, that wouldn't work.  I have been 
running a public ntp for several years now, and this is the only issue I have 
had. I do appreciate all the help on this topic.  Thanks again.


Time Zone is PST (GMT-8:00)

Date_flow_start          Duration Proto                             
Src_IP_Addr:Port                                 Dst_IP_Addr:Port   Packets    
Bytes Flows


2013-11-03 22:38:23.508    60.150 17                              67.#.#.#:123   
->                           162.#.#.#:80       19520  9135360     1


On Nov 4, 2013, at 19:54, Justin<[email protected]>  wrote:

I have two machines that participate in the ntp pool project, and I received an 
abuse email today. Basically, my server was DDOS someone else, ntp reflection 
attack.

Hi Justin,

Can you show a tcpdump of this?

I got two other DDOS related reports in the last 24 hours (which is at least 2 
more than I recall getting in any given*month*  or maybe even year in the last 
8!).

One was a straight up udp reflection attack (management packets, I think) - 
maybe similar to yours.

The other was udp packets, but not port 123 in either end. It looked like it was just a 
straight up "dump traffic that way" attack. That was multiple gigabits though.


Ask

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