[Ntp] NTP port randomization: close the port vs. keep port open

Fernando Gont <fgont@si6networks.com> Tue, 28 January 2020 03:57 UTC

To: "ntp@ietf.org" <ntp@ietf.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
From: Fernando Gont <fgont@si6networks.com>
Message-ID: <d889c321-0f38-8eec-986c-9813d5d0a996@si6networks.com>
Date: Mon, 27 Jan 2020 23:54:45 -0300
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Subject: [Ntp] NTP port randomization: close the port vs. keep port open
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Folks,

Another topic raised 
(https://mailarchive.ietf.org/arch/msg/ntp/9VDGNerkFM5E0rCmzuf019rfclo/) 
for the NTP port randomization draft )draft-ietf-ntp-port-randomization) 
is whether the I-D should recommend that clients close the port when 
they are not waiting for a response. This obviously reduces the attack 
window.

That is, we wonder if the I-D should recommend that if the client is not 
waiting for a response, or after a client has "timed out" waiting for a 
response, the client should close its port.

Thoughts?

Thanks!

Cheers,
-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492

[Ntp] NTP port randomization: close the port vs. … Fernando Gont