The program binds a port 123 and recieves clients requests. Each client is serving in new thread. Server sends a request to reliable NTP-server and makes a response to client. If there is no answer from this reliable NTP-server, it takes a time from a current machine. The value of version field in server response corresponds to a value of this field in clients request.
Choosen reliable NTP-server is pool.ntp.org. It can be changed in configurations of file listener.py.
Launcher of this server should have administrator permissions, because it binds a 123 port of a current host.
Server takes a one argument - shift of a time. So, it send shifted time to clients. Default value of shift is 0.
Server can be stoped any time during it works by typing a special command: "close". Closing command can be changed in configurations of a main file.
For a help message showing use --help or -h argument.