
Excessive DNS queries for NTP pool addresses - efftee
https://forum.flightradar24.com/threads/11042-Excessive-DNS-queries-for-NTP-pool-addresses
======
NelsonMinar
The NTP Pool has very simple guidelines for vendors distributing software with
hard-coded NTP server names. Very simply, they ask that you set up a vendor
DNS alias. Details here: [http://www.pool.ntp.org/en/vendors.html#basic-
guidelines](http://www.pool.ntp.org/en/vendors.html#basic-guidelines)

The NTP Pool is an incredibly valuable public resource. It's run by
volunteers, all they ask is you treat the resource with respect so it works
for everyone.

~~~
jimktrains2
Try explaining that to Poettering. [1] [2]

[1] [https://lists.freedesktop.org/archives/systemd-
devel/2014-Au...](https://lists.freedesktop.org/archives/systemd-
devel/2014-August/022575.html)

[2]
[https://github.com/systemd/systemd/issues/437](https://github.com/systemd/systemd/issues/437)

~~~
scrollaway
I think you linked something that has little to do with the subject at hand in
order to take a jab at Poettering. Lame behaviour.

The issue, as I remember it, is more complex than you suggest with your quip.
Who is the vendor for a distributed copy of systemd, is it systemd or the
distributor?

~~~
jsmthrowaway
Both threads are exactly about the subject of the discussion. How does it have
“little to do with the subject at hand?”

~~~
jryan49
I think the context that a lot of people seem to miss is that this default was
never used in practice with a real Linux distro. So in effect it was never
really an issue in the real world since the default was always changed.

~~~
jimktrains2
Then why provide a default at all? Especially one that isn't suppose to be
used publically like google's?

~~~
jryan49
So systemd at least compiles without manual settings, and convention over
configuration trends. It would be ideal if they just setup their own NTP
server for the default though. I think from a practical perspective though the
whole thing was blown out of proportion.

~~~
jimktrains2
It requires a configuration file to even compile? How's that work?

------
SiempreViernes
Later in the thread:

> I looked at it in some more detail a few hours after I posted this and it
> looks like this isn't a "normal" feature of the FR24 client but rather a
> failure to handle DNS problems gracefully. An issue with a local DNS server
> meant it was returning "domain not found" for some domains, including the
> *.pool.ntp.org domains.

> It seems the FR24 client has embedded calls to system programs to would find
> the first working (i.e successful ping) NTP host, sync up time from there
> and then carry on, but in this case as each host fails it tries the next in
> the list and when the list is exhausted it starts again from the top. Thus
> firing off an endless stream of DNS queries at a high rate until it manages
> to connect to an NTP server. The ICMP traffic wasn't actually generated in
> this case as the ping command fails because in my specific case the host
> address couldn't be found, for NTP servers that are in the pool but block
> ICMP this would generate traffic but still fail a ping.

> The local DNS problem turned out to be a misbehaving Pi-Hole installation on
> my home network refusing some DNS queries but it would be nice to see some
> kind of backoff algorithm or delay in the client, or preferably just insist
> on a working NTP client on the feeder rather than forced NTP syncs via
> external commands and a liberal use of ping.

Seems like the title is misleading.

~~~
acqq
It seems not, because, even later:

"fr24feed appears to be doing 12 NTP queries direct to servers around the
world every ten minutes, which is about three times as much load as the pool
recommends and appears to be a very high load on the parts of the world where
there are few volunteers running NTP servers"

[https://forum.flightradar24.com/threads/11042-Excessive-
DNS-...](https://forum.flightradar24.com/threads/11042-Excessive-DNS-queries-
for-NTP-pool-
addresses?s=9c2a36a984a38ff32360f8f3d10efc28&p=101240&viewfull=1#post101240)

~~~
SiempreViernes
While 1.2 vs 0.4 requests per minute is indeed a factor of three, calling it
"abuse" instead of something like "misconfigured" or "misuse" seems overblown.

What are you going to call the initial report of thousands of requests per
second then?

~~~
eropple
It's not overblown to characterize something about a system _you are told not
to do_ "abuse". If it is misuse, it is abuse. Words mean things.

~~~
freehunter
Words do in fact mean things, and that's why there's so many of them. Abuse
and misuse are two similar words with distinct connotations. Abusing something
means it's intentional and is causing significant harm. Misusing something
means using it in a way that could be accidental or intentional, but is
contrary to the way the thing should be used.

I have to agree with the other person, unless this was done intentionally and
the programmer knew it would cause damage, calling it abuse sounds overly
dramatic. I think the word misuse is far more accurate here.

~~~
eropple
Send an email to misuse@example.com and explain the problem and I'm sure
someone will get right on it.

Wait--you mean to tell me it's abuse@ _for a reason_...?

------
jimrandomh
This sounds like a bug (or maybe two bugs), not the result of any sort of
policy decision. So, before taking a combative stance and trying to shame them
into fixing it, it's important to make sure the relevant information has
actually reached the person who actually _could_ fix it, and they've had some
time to work!

~~~
sundvor
The first post in that thread was made 2017-05-03.

~~~
jimrandomh
Okay, but did it actually get read by the right person? It's very easy for bug
reports that came in the form of forum posts to slip by unnoticed. Or noticed
by tech support people who don't realize it might be worth escalating to dev.

------
reaperducer
I used to love FL24, until it stopped supporting its Mac client which I paid
for, rendering it useless. All you get is a message asking you to subscribe to
the program you've already paid for.

~~~
glup
What did the desktop client have that the web interface doesn't? Would love an
OS X client personally.

~~~
reaperducer
Primarily speed. Secondarily, the ability to display full-screen across a
27-inch display.

