Quoting Justin who wrote on Mon 2013-11-04 at 21:54:

> 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.  Obviously that is not something I want to  
> do.  By default my ntp server allows any that connect to port 123.   

Do you answer monitoring packets from the outside? These can be used in
attacks: the answers are bigger than the questions.

> These ddos were sending the responses back to someone's port 80, which  
> is causing me the headache.  My first step will be to lock the ntp down  
> to port 123 and ports above 1024 for people behind a nat.

Or simple clients... (ntpdate -u uses unprivileged ports for example).

                                                   Koos

-- 
Koos van den Hout,           PGP keyid DSS/1024 0xF0D7C263 via keyservers
[email protected]
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