This pair of programs keeps computer clocks accurate. Chronyd is a background program, and Chronyc is a command line interface to it. Time reference sources for Chronyd can be RFC1305 NTP servers, humans using the keyboard and Chronyc, and the computer s real-time clock at boot time. Chronyd can determine the rate at which the computer gains or loses time and compensate for it while no external reference is present. Chronyd s use of NTP servers can be switched on and off through Chronyc, to support computers with dial-up/intermittent access to the Internet. Chronyd can also act as an RFC1305-compatible NTP server.