Re: [Ntp] [tsvwg] [Tsv-art] Tsvart early review of draft-ietf-ntp-alternative-port-02

[Miroslav Lichvar <[e-mail]>]

On Sun, Dec 05, 2021 at 03:20:12PM -0800, C. M. Heard wrote:
> We have two contradictory assertions by proponents of the alternate port.
> Which, if either, is correct?
> 
> Are the servers largely fixed but the filters still in place out of
> inertia, as Mr. Sommers says?
> 
> Or do the filters remain because of servers that have not been fixed, as
> Mr. Murray says?

I suspect we won't know for sure as long as NTP is firewalled
everywhere.

The reality is that NTP doesn't work reliably over Internet. In the
community of people running public servers (pool.ntp.org) it's the
number one problem. My impression is that it's getting worse over
time.

With NTS, which uses longer NTP messages it's quite common to see a
client that doesn't get a response to most of its requests.

The major ISPs have middleboxes, which cannot be configured to
specifically block or rate limit the amplifiying mode-6/7 messages.
Better hardware could be designed, but who will pay for that?
Expecting all those existing servers that amplify the traffic to be
fixed and the middleboxes to be disabled doesn't seem to be realistic.

-- 
Miroslav Lichvar