Basic command

w32tm /stripchart /computer:time.example.com

The command continues until stopped with Ctrl+C.

Take a fixed number of samples

w32tm /stripchart /computer:time.example.com /samples:5 /dataonly

This is the most useful form for routine testing and documentation.

/computer

Specifies the hostname or IP address to test.

/computer:0.uk.pool.ntp.org
/computer:time.example.com
/computer:DC01

Use a hostname where DNS is part of the design. Testing only an IP address can hide a DNS problem.

/samples

/samples:5

Stops after the specified number of measurements.

/dataonly

Displays the measured offset without the strip-chart graphic.

w32tm /stripchart /computer:time.example.com /samples:5 /dataonly

/period

w32tm /stripchart /computer:time.example.com /period:2

Sets the interval between samples in seconds.

/packetinfo

w32tm /stripchart /computer:time.example.com /samples:1 /packetinfo

Displays additional NTP packet information. This is useful when checking stratum, reference details and whether the response looks like valid NTP data.

Reading the output

A typical data-only result resembles:

18:45:01, -00.0008123s
18:45:03, -00.0007451s
18:45:05, -00.0007904s

A negative value means the local clock is behind the target by the displayed amount. A positive value means it is ahead.

Small differences are normal. Large or rapidly changing offsets require investigation.

Test an external peer

w32tm /stripchart /computer:0.uk.pool.ntp.org /samples:5 /dataonly

If this fails, check DNS, routing, firewall rules and whether the public service permits the request.

Test an internal source

w32tm /stripchart /computer:time.example.com /samples:5 /dataonly

This verifies that the organisational DNS name resolves and the target responds.

Test a domain controller

w32tm /stripchart /computer:DC01 /samples:5 /dataonly

This is useful when comparing a member computer with the DC it is expected to use.

Why stripchart can work when normal sync fails

stripchart and normal Windows Time synchronisation do not use the UDP source port in exactly the same way. A firewall can therefore permit the diagnostic test while blocking the normal W32Time client.

If stripchart works but w32tm /resync reports no time data, review:

  • The peer mode and flags.
  • UDP 123 source and destination rules.
  • The configured type and peer list.
  • Whether Group Policy is overriding local settings.
  • Whether the server is returning usable, synchronised time.

Timeouts

A timeout usually indicates one of the following:

  • The hostname did not resolve correctly.
  • The target is not running an NTP service.
  • UDP 123 is blocked.
  • The target permits only selected client networks.
  • Routing to the server is unavailable.

Microsoft documentation

Related information