metasystema.org
CurrentPROPOSED STANDARDIETF stream

RFC 9109: Network Time Protocol Version 4: Port Randomization

In plain English — editorial summary, not part of the RFC

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.

Document record

Document ID
RFC9109
Published
August 2021
Authors
F. Gont; G. Gont; M. Lichvar
Status
PROPOSED STANDARD
Stream
IETF
Area
int
Pages
9
Also known as
—
Updates:
RFC 5905

Topics

Related documents

Ranked automatically by shared keywords, IETF area and stream — not by editorial selection.

Also filed under

About this page

The document record above — title, authors, date, status, stream, area, relationships, DOI and errata — is imported verbatim from the public RFC Editor index. The “in plain English” section is editorial: written by The metasystema editorial team, not part of the RFC. Where the two differ, the RFC text governs.

Last checked against the RFC Editor index on . RFCs are never revised after publication; changes are issued as new documents.

Data sources · Editorial policy · Report a correction · What is an RFC?

canonical URL: /rfc/9109-network-time-protocol-version-4-port-randomization