[rfc-dist] RFC 9109 on Network Time Protocol Version 4: Port Randomization

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Mon Aug 23 21:29:14 PDT 2021

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        RFC 9109

        Title:      Network Time Protocol Version 4: 
                    Port Randomization 
        Author:     F. Gont,
                    G. Gont,
                    M. Lichvar
        Status:     Standards Track
        Stream:     IETF
        Date:       August 2021
        Mailbox:    fgont at si6networks.com,
                    ggont at si6networks.com,
                    mlichvar at redhat.com
        Pages:      9
        Updates:    RFC 5905

        I-D Tag:    draft-ietf-ntp-port-randomization-08.txt

        URL:        https://www.rfc-editor.org/info/rfc9109

        DOI:        10.17487/RFC9109

The Network Time Protocol (NTP) can operate in several modes.  Some
of these modes are based on the receipt of unsolicited packets and
therefore require the use of a well-known port as the local port. 
However, in the case of NTP modes where the use of a well-known port
is not required, employing such a well-known port unnecessarily
facilitates the ability of attackers to perform blind/off-path
attacks. This document formally updates RFC 5905, recommending the
use of transport-protocol ephemeral port randomization for those
modes where use of the NTP well-known port is not required.

This document is a product of the Network Time Protocol Working Group of the IETF.

This is now a Proposed Standard.

STANDARDS TRACK: This document specifies an Internet Standards Track
protocol for the Internet community, and requests discussion and suggestions
for improvements.  Please refer to the current edition of the Official
Internet Protocol Standards (https://www.rfc-editor.org/standards) for the 
standardization state and status of this protocol.  Distribution of this 
memo is unlimited.

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