Filter NTP traffic by packet size?
nick at foobar.org
Sat Feb 22 15:06:32 UTC 2014
On 22/02/2014 09:07, Cb B wrote:
> Summary IETF response: The problem i described is already solved by
> bcp38, nothing to see here, carry on with UDP
udp is here to stay. Denying this is no more useful than trying to push
the tide back with a teaspoon.
It's worth bearing in mind that any open tcp service will send out several
acks before giving up. In other words, any standard open tcp socket will
provide a level of amplification worth using even if UDP were to be
switched off tomorrow. Sure, not as good as the 230x amplification that
ntp monlist will give, but it's still a problem.
In the long term, it would be more useful to spent time and effort building
automated tools to track down the sources of the spoofed packets than
trying to deprecate UDP.
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