It's not always obvious that a firewall even exists as they generally allow regular web traffic to pass normally.

NetTime is failing to sync - it reports that all servers failed: The most common cause of this error is that a firewall is blocking the Network Time Protocol (UDP Port 123) between your system and the servers that NetTime is attempting to use. If you uninstall the old version first, you will need to restart your computer before starting the new installer. Note: When upgrading from a previous version, you will need to shut down both the NetTime Service as well as the Tray Icon before running the installer. Previous versions as well as the source code can be downloaded from the SourceForge project page Version 3.20 Alpha 3 - Latest Test Version: Version 3.20 Alpha 1 - Previous Test Version: If you find NetTime useful, please consider making a donation to show your appreciation and to encourage further development of NetTime! The NetTime project has been resurrected by myself, Mark Griffiths, and I'm now making an updated version available here: Graham made a number of updates to the program until he lost interest and finally abandoned the project officially on the 1st of July 2004. NetTime was originally written by Graham Mainwaring in 1997 with an open source release made in 1998.

If you're looking for a program to keep your system time accurate, you've just found it! (32 bit and 64 bit operating systems are both supported) NetTime - Network Time Synchronization Tool NetTime

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