On Feb 12, 2014, at 6:46 AM, omar parihuana <[email protected]> wrote:

> I've just put an ACL in order to block NTP outbound traffic.

You should look at the ntp sources, find out which allow monlist, et. al. (see 
<http://www.openntpproject.org/>), then work to remediate those specific ntpds. 
 Blocking ntp traffic wholesale is something which might make sense in an 
emergency as you describe, for a  brief time, but which shouldn't be done any 
longer than is absolutely necessary.

btw, you don't need NBAR to detect/classify this traffic - regular NetFlow will 
do.  NBAR eats up a lot more resources on your box.

-----------------------------------------------------------------------
Roland Dobbins <[email protected]> // <http://www.arbornetworks.com>

          Luck is the residue of opportunity and design.

                       -- John Milton


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