[Pool] 8-10k pps in Brazil

Denis Corbin news at edrusb.is-a-geek.org
Sat May 23 09:24:37 UTC 2015


On 22/05/2015 20:47, Maximiliano Valdez wrote:
> Matt, sorry for the duplicity, I forgot to reply to the list

Hi all,

> Hi Matt
> 
> I wonder if this behaviour is the result of some kind of load balancing
> error on ntp.org DNS or something.
> 

An DoS attack using IP source spoofing could cause the same behavior
from the attacked server point of view. Difficult to know whether this
is a load balancing error or an single attack.

However, if the NT pool is reduced for Brazil due to some network issues
for example, the behavior is different: all server still remaining in
the pool should see the same load increase, well, more or less.

The number of active server in the Brazil pool is available at
http://www.pool.ntp.org/zone/br

First there is a small number of servers and load balancing may
statistically be unfair more often than for a larger pool. Second, the
number of active server dropped from 20 down to 9 since the beginning of
the year. This alone could explain the load increase Matt observes on
his server.

Reducing the bandwidth in "Manage your servers" will increase the load
the other servers which might lead their respective maintainers to
reduce the bandwidth allocation at the same place which will increase
back the load on your server...

Cheers,
Denis.



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