The Network Time Protocol (NTP) is a protocol for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks like Internet. The pool.ntp.org project is a big virtual cluster of timeservers providing reliable easy to use NTP service for millions of clients. Unfortunately NTP cannot be used everywhere without problems. NTP uses UDP on port 123 as its transport layer, and that could be blocked by the firewall in many places.
HTP Time Sync is one alternative way to get correct time to your computer. It uses the HTTP protocol for time synchronization. Every Web server runs HTTP and, by definition, Web servers always respond to HTTP requests with their current date and time. The current time and date information is available on the HTTP header text line that starts with text “Date:”.
You can use whatever suitable tools to write a simple script that gets that time (tip: you can connect to web server with nc or telnet instead of big bew browser software) or you can use ready made software you can find at HTTP Time Protocol / htpdate web page.