Ntp Workgroup RFCs

Browse Ntp Workgroup RFCs by Number

RFC5905 - Network Time Protocol Version 4: Protocol and Algorithms Specification
The Network Time Protocol (NTP) is widely used to synchronize computer clocks in the Internet. This document describes NTP version 4 (NTPv4), which is backwards compatible with NTP version 3 (NTPv3), described in RFC 1305, as well as previous versions of the protocol. NTPv4 includes a modified protocol header to accommodate the Internet Protocol version 6 address family. NTPv4 includes fundamental improvements in the mitigation and discipline algorithms that extend the potential accuracy to the tens of microseconds with modern workstations and fast LANs. It includes a dynamic server discovery scheme, so that in many cases, specific server configuration is not required. It corrects certain errors in the NTPv3 design and implementation and includes an optional extension mechanism. [STANDARDS-TRACK]
RFC5906 - Network Time Protocol Version 4: Autokey Specification
This memo describes the Autokey security model for authenticating servers to clients using the Network Time Protocol (NTP) and public key cryptography. Its design is based on the premise that IPsec schemes cannot be adopted intact, since that would preclude stateless servers and severely compromise timekeeping accuracy. In addition, Public Key Infrastructure (PKI) schemes presume authenticated time values are always available to enforce certificate lifetimes; however, cryptographically verified timestamps require interaction between the timekeeping and authentication functions.
This memo includes the Autokey requirements analysis, design principles, and protocol specification. A detailed description of the protocol states, events, and transition functions is included. A prototype of the Autokey design based on this memo has been implemented, tested, and documented in the NTP version 4 (NTPv4) software distribution for the Unix, Windows, and Virtual Memory System (VMS) operating systems at http://www.ntp.org. This document is not an Internet Standards Track specification; it is published for informational purposes.
RFC5907 - Definitions of Managed Objects for Network Time Protocol Version 4 (NTPv4)
The Network Time Protocol (NTP) is used in networks of all types and sizes for time synchronization of servers, workstations, and other networked equipment. As time synchronization is more and more a mission-critical service, standardized means for monitoring and management of this subsystem of a networked host are required to allow operators of such a service to set up a monitoring system that is platform- and vendor-independent. This document provides a standardized collection of data objects for monitoring the NTP entity of such a network participant and it is part of the NTP version 4 standardization effort. [STANDARDS-TRACK]
RFC5908 - Network Time Protocol (NTP) Server Option for DHCPv6
The NTP Server Option for Dynamic Host Configuration Protocol for IPv6 (DHCPv6) provides NTPv4 (Network Time Protocol version 4) server location information to DHCPv6 hosts. [STANDARDS-TRACK]
RFC7821 - UDP Checksum Complement in the Network Time Protocol (NTP)
The Network Time Protocol (NTP) allows clients to synchronize to a time server using timestamped protocol messages. To facilitate accurate timestamping, some implementations use hardware-based timestamping engines that integrate the accurate transmission time into every outgoing NTP packet during transmission. Since these packets are transported over UDP, the UDP Checksum field is then updated to reflect this modification. This document proposes an extension field that includes a 2-octet Checksum Complement, allowing timestamping engines to reflect the checksum modification in the last 2 octets of the packet rather than in the UDP Checksum field. The behavior defined in this document is interoperable with existing NTP implementations.
RFC7822 - Network Time Protocol Version 4 (NTPv4) Extension Fields
The Network Time Protocol version 4 (NTPv4) defines the optional usage of extension fields. An extension field, as defined in RFC 5905, is an optional field that resides at the end of the NTP header and that can be used to add optional capabilities or additional information that is not conveyed in the standard NTP header. This document updates RFC 5905 by clarifying some points regarding NTP extension fields and their usage with Message Authentication Codes (MACs).
RFC8573 - Message Authentication Code for the Network Time Protocol
The Network Time Protocol (NTP), as described in RFC 5905, states that NTP packets should be authenticated by appending NTP data to a 128-bit key and hashing the result with MD5 to obtain a 128-bit tag. This document deprecates MD5-based authentication, which is considered too weak, and recommends the use of AES-CMAC as described in RFC 4493 as a replacement.
RFC8633 - Network Time Protocol Best Current Practices
The Network Time Protocol (NTP) is one of the oldest protocols on the Internet and has been widely used since its initial publication. This document is a collection of best practices for the general operation of NTP servers and clients on the Internet. It includes recommendations for the stable, accurate, and secure operation of NTP infrastructure. This document is targeted at NTP version 4 as described in RFC 5905.
RFC8877 - Guidelines for Defining Packet Timestamps
Various network protocols make use of binary-encoded timestamps that are incorporated in the protocol packet format, referred to as "packet timestamps" for short. This document specifies guidelines for defining packet timestamp formats in networking protocols at various layers. It also presents three recommended timestamp formats. The target audience of this document includes network protocol designers. It is expected that a new network protocol that requires a packet timestamp will, in most cases, use one of the recommended timestamp formats. If none of the recommended formats fits the protocol requirements, the new protocol specification should specify the format of the packet timestamp according to the guidelines in this document.
RFC8915 - Network Time Security for the Network Time Protocol
This memo specifies Network Time Security (NTS), a mechanism for using Transport Layer Security (TLS) and Authenticated Encryption with Associated Data (AEAD) to provide cryptographic security for the client-server mode of the Network Time Protocol (NTP).
NTS is structured as a suite of two loosely coupled sub-protocols. The first (NTS Key Establishment (NTS-KE)) handles initial authentication and key establishment over TLS. The second (NTS Extension Fields for NTPv4) handles encryption and authentication during NTP time synchronization via extension fields in the NTP packets, and holds all required state only on the client via opaque cookies.
RFC9109 - Network Time Protocol Version 4: Port Randomization
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.
RFC9249 - A YANG Data Model for NTP
This document defines a YANG data model that can be used to configure and manage Network Time Protocol (NTP) version 4. It can also be used to configure and manage version 3. The data model includes configuration data and state data.
RFC9327 - Control Messages Protocol for Use with Network Time Protocol Version 4
This document describes the structure of the control messages that were historically used with the Network Time Protocol (NTP) before the advent of more modern control and management approaches. These control messages have been used to monitor and control the NTP application running on any IP network attached computer. The information in this document was originally described in Appendix B of RFC 1305. The goal of this document is to provide an updated description of the control messages described in RFC 1305 in order to conform with the updated NTP specification documented in RFC 5905.
The publication of this document is not meant to encourage the development and deployment of these control messages. This document is only providing a current reference for these control messages given the current status of RFC 1305.
RFC9523 - A Secure Selection and Filtering Mechanism for the Network Time Protocol with Khronos
The Network Time Protocol version 4 (NTPv4), as defined in RFC 5905, is the mechanism used by NTP clients to synchronize with NTP servers across the Internet. This document describes a companion application to the NTPv4 client, named "Khronos", that is used as a "watchdog" alongside NTPv4 and that provides improved security against time-shifting attacks. Khronos involves changes to the NTP client's system process only. Since it does not affect the wire protocol, the Khronos mechanism is applicable to current and future time protocols.