[ntp:questions] NTP Pool & Network Load (Was: zeroconf for ntpd?)

Jason Rabel jason at extremeoverclocking.com
Sat May 26 20:53:28 UTC 2007

I think that any home user that is running *nix machines with NTP would know
better than to have them all sync to pool servers. I'm sure a good majority
have their own little hierarchy. As for windows machines, with most people
just running the default windows SNTP client... I don't want to get into

One thing I think would be nice is if home broadband routers started to
implement NTP (or even just SNTP) server abilities (for the LAN side only by
default). That way local LAN clients could just sync to the router.

Anyhow, I had to pull my server (this is the 2nd time) from the NTP pool
because of load/network issues that only cropped up once I joined the pool,
and since I removed myself and configured NTP not to respond to network
requests it has gone away.

It wasn't the usual traffic that was causing problems, but a handful of
abusive clients. I monitor and log everything, NTP connections were no
exception. Even after I started to block some IPs via my firewall I would
still get pounded with thousands of requests daily from them. Even though my
server is at a hosting facility with a 100Mb connection, with only the
minimum speed set in the NTP Pool (256k?) I was having those problems! I'm
sure I am not the only one that has experienced such issues, and for those
using a DSL/Cable connection with much less bandwidth the problem has to be
more intensified.

I don't know if it was intentional abuse or just some poorly written clients
(perhaps some routers or other appliances, I don't know). Either way it is
not good for the pool project, and as the pool grows (hopefully) the issue
will probably only worsen if people continue to ignore it.


>>>The problem I see is that the current setup is quite wasteful.  If a
>>>home user has 3 running systems, it beats up on 3x4 pools servers. 
>>>That is 3x more load than strictly needed, especially since pools
>>>servers are already being hit up for 15 ntp queries per second.  It
>>>would be good to figure out a way to lower that load and be able to
>>>serve the rest of the 99% of the systems that currently aren't using
>>>ntp yet.
>> I may be missing something, but 15 queries a second - that's pretty
>> much a "nothing" load. A hundred times that should still be well
>> within the capabilities of a "T1" connection, never mind that of
>> a Pentium grade based system.
>The problem is the 15 queries/sec is an average.  The peaks appear to
>be 10x that and cause the consumer ADSL or cable lines to overload.
>Folks are talking about bailing out of being ntp pool volunteers.  I
>can easily see the ntp pool collapse due to positive feedback effects.
>(If the load is too high and some folks bail the load will get even
>higher causing a general run for the door.)  Something that is as easy
>to setup as pools but much lower load is needed.  We are still only at
>1% ntp penetration (2-6 million pools users out of 400 million
>internet-connected computers.)  The load is going to go up quite a bit
>as more of the old computers are replaced or have their SW updated.
>        http://fortytwo.ch/mailman/pipermail/timekeepers/2007/002936.html

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