GW32TIME

GW32TIME is a small Windows utility for inspecting, validating, and managing the Windows Time service (W32Time). It provides both a graphical interface and a CLI for common operator tasks: checking service health, reviewing configured NTP servers, testing NTP quality, changing manual peers, applying safe presets, backing up/restoring configuration, adjusting polling, requesting resync, and setting the local date/time.

The project targets old and constrained Windows systems as well as modern systems. The default build produces a 32-bit Windows executable with an XP-era subsystem version and avoids SIMD instructions.

Key Features

• GUI for Windows Time status and configuration.
• CLI for scripted and interactive operations.
• Health diagnostics for W32Time service state and basic registry settings.
• NTP server list parsing and editing with Windows peer flags.
• Built-in NTP checker with reachability, delay, offset, jitter, score, stratum, validation reason, IP, and PTR surface.
• Guardrails for domain-joined machines, aggressive polling, non-elevated writes, and invalid server names.
• Backup and restore of relevant W32Time configuration.
• UAC-assisted GUI operations for privileged changes.
• Release builds from semantic version tags such as 1.2.3.

Supported Platform

GW32TIME is a native Win32 application. The Makefile currently builds with the i686-w64-mingw32 toolchain.

Build characteristics:

• Target: gw32time.exe
• Architecture: i386 / 32-bit Windows
• Unicode entry point and UI strings
• Windows subsystem version: 5.1
• Compiler flags disable SSE, SSE2, MMX, and related SIMD code generation
• make verify checks the subsystem version, binary size, and SIMD instruction surface

GUI Overview

Running gw32time.exe without arguments opens the GUI.

The main window shows:

• Health status
• Windows Time service state
• Service start mode
• Synchronization type
• Poll interval controls
• Configured server table
• Live current local time
• UAC status indicator

Main actions:

• Service: start, stop, restart, and change service start mode.
• Backup & Restore: save or restore Windows Time configuration.
• Sync Now: request a w32tm /resync.
• Add, Update, Delete: edit NTP peer rows.
• Apply Servers: write the displayed peer list to W32Time.
• Date & Time: set local date/time through a privileged path.
• Check Servers: run NTP checks and populate validation metrics.
• Realtime Check: periodically re-check configured servers.

Date & Time UI

The Date & Time action opens a focused editor for local date and time.

Behavior and guardrails:

• UAC is requested before entering the date/time editor when the current process cannot adjust system time.
• A successful UAC prompt is not treated as enough by itself; the elevated token must actually have SeSystemtimePrivilege.
• If the selected elevated account lacks the right to change system time, the helper is closed so the next click prompts for UAC again.
• If the current process already has the needed privilege, it sets time directly.
• The editor suppresses live refresh for fields the user has started editing.
• On first input into a field, the auto-filled value is cleared so only the user-entered digits remain.
• Input is length-limited: year is 4 digits; month, day, hour, minute, and second are 2 digits each.

CLI Usage

gw32time --help
gw32time --version
gw32time status [--raw] [--verbose]
gw32time gui
gw32time runtime
gw32time health
gw32time diag [--raw]
gw32time service status|start|restart
gw32time servers list
gw32time servers test <host>
gw32time checker <host...> [--samples N] [--timeout MS] [--interval MS] [--port N] [--parallel] [--explain] [--json]
gw32time servers set <host...> [--dry-run] [--yes] [--no-sync] [--force-domain]
gw32time poll get
gw32time poll set <seconds> [--dry-run] [--yes] [--force]
gw32time preset list
gw32time preset desktop|lab-fast|windows-default|domain [--dry-run] [--yes]
gw32time sane [--dry-run] [--yes]
gw32time backup <file>
gw32time restore <file> [--dry-run] [--yes]
gw32time menu
gw32time sync [--yes]

Status and Diagnostics

Use:

gw32time status
gw32time status --verbose
gw32time status --raw
gw32time health
gw32time diag
gw32time diag --raw

These commands read service state, start type, registry-backed W32Time settings, and selected w32tm outputs. health condenses the result to one state:

• OK: service and basic configuration look usable.
• WARNING: configuration is suspicious but not necessarily unusable.
• BROKEN: service/configuration cannot work as-is.
• UNKNOWN: required state could not be queried.

Health checks include:

• Whether the Windows Time service state is readable.
• Whether the service start type is readable.
• Whether the service is disabled.
• Whether the service is running.
• Whether W32Time registry configuration is readable.
• Whether Type=NoSync is configured.
• Whether the NTP client provider is disabled.
• Whether NTP/manual modes have a non-empty server list.
• Whether w32tm /query /status completes successfully.

Service Operations

gw32time service status
gw32time service start
gw32time service restart

Changing service state requires an elevated administrator token. The GUI also offers service start/stop/restart and start-mode actions.

Server List Operations

gw32time servers list
gw32time servers set time.cloudflare.com pool.ntp.org --dry-run
gw32time servers set time.cloudflare.com pool.ntp.org --yes
gw32time servers test time.cloudflare.com

servers list reads the configured NtpServer registry value and prints the parsed peers and flags.

servers set builds a manual NTP peer list and applies it through both registry write and w32tm /config /manualpeerlist:... /syncfromflags:manual /update. After that it restarts w32time and, unless --no-sync is used, requests a resync.

Default peer behavior:

• Each CLI peer is formatted with 0x8 client-mode flags.
• Host names may not be empty.
• Host names reject spaces, commas, quotes, backslashes, and slashes.
• The peer list is bounded by the project NTP peer limit.

Polling Interval

gw32time poll get
gw32time poll set 1024 --dry-run
gw32time poll set 1024 --yes

poll get prints known polling values, including SpecialPollInterval when available.

poll set writes SpecialPollInterval, runs w32tm /config /update, and restarts w32time.

Guardrails:

• Values below 64 seconds are rejected unless --force is used.
• Values below 256 seconds print an aggressive-polling warning.
• Values above one day print a long-polling warning.
• Applying changes requires elevation.
• Without --yes, the CLI asks for confirmation.

Presets

gw32time preset list
gw32time preset desktop --dry-run
gw32time preset lab-fast --yes
gw32time preset windows-default --yes
gw32time preset domain --yes

Available presets:

Preset	Mode	Servers	Poll
desktop	NTP	time.cloudflare.com,0x8 pool.ntp.org,0x8 time.google.com,0x8	1024 sec
lab-fast	NTP	time.cloudflare.com,0x8 pool.ntp.org,0x8	256 sec
windows-default	NTP	time.windows.com,0x8	604800 sec
domain	NT5DS	unchanged	unchanged

Presets are applied by writing relevant W32Time registry values, running w32tm /config /update, and restarting the service.

Backup and Restore

gw32time backup w32time-backup.ini
gw32time restore w32time-backup.ini --dry-run
gw32time restore w32time-backup.ini --yes

Backup writes the current W32Time configuration to a local file. Restore previews the differences, asks for confirmation unless --yes is used, writes the saved configuration back, runs w32tm /config /update, and restarts w32time.

NTP Server Analysis

GW32TIME includes a custom NTP checker rather than relying only on w32tm status. It actively sends NTP client requests and evaluates the responses.

What Is Measured

For each server check, GW32TIME can report:

• Reach: successful samples over total samples.
• Delay: mean network delay.
• Dmin: minimum observed delay.
• Offset: median clock offset.
• Mean: mean offset.
• Stddev: standard deviation of filtered offsets.
• MAD: median absolute deviation of filtered offsets.
• Jitter: currently based on offset standard deviation.
• Score: normalized quality score from 0.00 to 1.00.
• Stratum: NTP stratum from the response.
• Valid: whether a successful probe result is available.
• Reason: last validation or socket reason.
• KoD/refid: kiss-of-death reference ID when applicable.
• IP: resolved/probed IP surface in GUI rows.
• PTR: reverse DNS surface in GUI rows.

Default Checker Configuration

The default checker configuration is:

• Samples: 5
• Timeout: 800 ms
• Interval between samples: 150 ms
• Port: 123
• Outlier threshold: 50 ms

The simpler gw32time servers test <host> command uses the checker with a shorter interval of 120 ms.

Protocol Validation

Each NTP response is validated before it contributes to statistics.

Rejected cases include:

• DNS failure.
• Socket failure.
• Timeout.
• Short packet.
• Response mode is not server mode.
• NTP version is not 3 or 4.
• Leap indicator is 3, which means unsynchronized.
• Stratum is 0, which is treated as kiss-of-death.
• Stratum is above 15.
• Receive or transmit timestamp is zero.
• Originate timestamp is missing or does not match the request transmit timestamp.
• Non-primary stratum response has zero reference timestamp.
• Transmit timestamp is earlier than receive timestamp.
• Local receive timestamp is earlier than local send timestamp.
• Computed delay is less than -1 ms.

Small negative delay caused by precision or clock granularity is clamped to zero.

Offset and Delay Formula

For a valid NTP sample, GW32TIME uses the standard four-timestamp model:

• t1: local send time
• t2: server receive time
• t3: server transmit time
• t4: local receive time

Offset:

((t2 - t1) + (t3 - t4)) / 2

Delay:

(t4 - t1) - (t3 - t2)

GW32TIME records both wall-clock NTP timestamps and a local monotonic RTT sample for transport timing.

Outlier Handling

Successful offsets are filtered with a median-based outlier filter. The default threshold is 50 ms. If filtering fails or removes all samples, the checker falls back to all successful offsets instead of returning no statistics.

Reported statistics include median, mean, standard deviation, minimum delay, mean delay, and MAD.

Score

The score starts at 1.0, is multiplied by reachability, and then receives penalties:

• Minimum delay above 100 ms: -0.15
• Jitter above 10 ms: -0.20
• Absolute median offset above 100 ms: -0.25
• Stratum 8 or higher: -0.10
• Any failed samples: -0.05

The final score is clamped to the 0.0 to 1.0 range.

Explanations

With --explain, or through GUI detail surfaces, the checker can emit compact notes such as:

• reachability percentage
• low/high jitter
• low/high delay
• median offset
• MAD
• KoD/refid detail

IPv4 and IPv6

The checker resolves with AF_UNSPEC, so both IPv4 and IPv6 endpoints can be used. It also accepts bracketed IPv6 literals, such as:

gw32time checker [2001:4860:4806:8::]

For safety, a response is rejected if the sender address family does not match the endpoint family being probed.

Guardrails and Safety Model

GW32TIME is intentionally conservative around system time changes. It tries to make risky operations explicit, previewable, and reversible.

Elevation

Registry writes, service changes, resync operations that need service start, and local time changes require a privileged token.

The GUI can start an elevated helper through UAC. For Date & Time, the helper is not accepted only because UAC succeeded; it must prove it can enable SeSystemtimePrivilege.

Domain-Joined Machines

Manual NTP server changes are refused on domain-joined machines unless --force-domain is supplied.

Reason: domain machines commonly receive time hierarchy and policy from the domain. Forcing manual NTP can conflict with domain expectations or be reverted by policy.

Dry Runs

Most mutating CLI operations support --dry-run, including:

• servers set
• poll set
• preset ...
• restore
• sane

Dry-run output prints the current state, the desired state, and the exact action plan.

Confirmation

Mutating CLI operations ask for confirmation by default. Use --yes for non-interactive automation.

Polling Bounds

Very aggressive polling is blocked below 64 seconds unless --force is used. Moderately aggressive values below 256 seconds warn the operator.

Backup Before Restore

The restore path previews changes before writing them. Operators should keep a backup made with:

gw32time backup <file>

before applying large server/preset changes.

Input Validation

Server names supplied to servers set are validated before formatting. Empty hosts and hosts containing whitespace, commas, quotes, backslashes, or slashes are rejected.

Date/time fields in the GUI are numeric and length-limited.

Build

Install MinGW-w64 i686 tools and make, then run:

make

The default output is:

gw32time.exe

Clean generated artifacts:

make clean

Verify the executable:

make verify

make verify checks:

• PE subsystem major/minor version
• binary size
• absence of selected SIMD instruction mnemonics in disassembly

Versioned Builds

The build accepts a VERSION variable:

make VERSION=1.2.3

That version is compiled into:

• CLI --version output
• GUI main window title, for example GW32TIME 1.2.3

Changing VERSION creates a version stamp under build/ so the executable is relinked when the version changes.

GitHub Actions

Try Workflow

.github/workflows/try.yml runs on every push and pull request.

It has two independent jobs so GitHub Actions can run them in parallel:

• Test build: builds build/gw32time-test.exe using the existing Makefile with TARGET=build/gw32time-test.exe and STRIP=: overrides.
• Smoke tests: runs bash scripts/smoke/run.sh.

Release Workflow

.github/workflows/release.yml runs on pushed tags matching *.*.* and then validates that the tag is exactly semantic-version-like:

1.2.3

The release workflow:

1. Checks out the repository.
2. Validates the tag.
3. Installs the MinGW toolchain.
4. Builds with make VERSION="$VERSION".
5. Runs make VERSION="$VERSION" verify.
6. Packages gw32time.exe.
7. Writes a SHA-256 checksum.
8. Uploads a GitHub Actions artifact.
9. Publishes a GitHub Release with the executable and checksum.

Tests are intentionally not duplicated in release.yml because the try.yml workflow already runs on the push.

Smoke Tests

The smoke runner is:

bash scripts/smoke/run.sh

Current smoke checks cover:

• Build and make verify.
• CLI checker command surface.
• GUI NTP table columns and checker fields.
• IPv6-ready NTP socket surface.

The smoke scripts are source-surface and build-surface checks. They are designed to be stable in CI without needing live network access to a specific NTP server.

Artifact Hygiene

Generated build outputs are ignored by .gitignore, including:

• build/
• dist/
• release/
• *.exe
• *.dll
• *.o
• *.obj
• *.res
• release archives and checksums
• linker/debug outputs
• local build logs

Operational Notes

• Prefer --dry-run before changing servers, presets, polling, or restoring a backup.
• Use gw32time health before making changes to understand the current failure mode.
• Use gw32time servers test <host> or gw32time checker <host...> before applying a new NTP server list.
• On domain-joined machines, prefer the domain preset unless there is an explicit reason to override domain time hierarchy.
• Keep polling conservative on production systems.
• If resync fails, inspect gw32time diag --raw and the raw w32tm output.

Troubleshooting

Sync Requires Elevation

Run the CLI from an elevated console or use the GUI UAC flow.

Server Changes Refused on Domain Machine

Use --force-domain only when you intentionally want manual NTP on a domain-joined system.

No Successful NTP Samples

Check:

• DNS resolution.
• UDP/123 reachability.
• Local firewall policy.
• Whether the server returns KoD.
• Whether the server response has valid mode/version/timestamps.
• Whether IPv6 routing is available when probing an IPv6 literal.

High Jitter or Poor Score

Try multiple servers and compare:

• reachability
• minimum delay
• median offset
• MAD
• jitter
• stratum

Prefer a server with high reachability, low delay, low jitter, small absolute median offset, and a reasonable stratum.