NTP Server Tool

Packet Header:

• Leap Indicator (LI): Warns of a leap second at the end of the current day.
  • 0: No leap second adjustment.
  • 1: Last minute of the day has 61 seconds.
  • 2: Last minute of the day has 59 seconds.
  • 3: Clock is unsynchronized.
• Version Number (VN): The version of the protocol in use. Version 3 is defined by RFC 1305 and version 4 by RFC 5905.
• Mode: The role the sender is taking in the exchange.
  • 0: Reserved.
  • 1: Symmetric Active.
  • 2: Symmetric Passive.
  • 3: Client.
  • 4: Server.
  • 5: Broadcast.
  • 6: NTP control message.
  • 7: Private use.
• Stratum: How many steps the server is removed from a primary reference clock.
  • 0: Unspecified or invalid.
  • 1: Primary reference.
  • 2-15: Secondary reference.
  • 16: Unsynchronized.
  • 17-255: Reserved.
• Poll Interval: The maximum interval between messages in seconds to the nearest power of two.
• Precision: Precision of the local clock in seconds to the nearest power of two.

Reference Clock:

• Reference ID (REFID): Used to identify the particular reference clock.
  • In the case of stratum 0 (unspecified) or stratum 1 (primary reference), this is a four byte, left-justified, zero padded ASCII string.
  • In the case of stratum 2 and greater (secondary reference) this is the IPv4 address of the primary reference host.
• Reference Timestamp (REF TIME): The local time at which the local clock was last set or corrected.
• Root Dispersion (DISP): The maximum error relative to the primary reference source in seconds with the fraction point between bits 15 and 16. Only positive values greater than zero are valid.
• Round Trip Delay: The time between the departure of request and arrival of reply in milliseconds.

Timestamps:

• Originate Timestamp (ORG): The local time when the client sent the request.
• Receive Timestamp (REC): The local time when the request was received by the server.
• Transmit Timestamp (XMT): The local time when the reply was sent from the server.

Local System:

• Local System Time (SYS): The current time and date on the local system.
• Local Clock Offset: The offset of the local clock relative to the primary reference source in milliseconds.