The purpose of having a maximum disparity is to keep your machine from accepting time from a server that has "gone mad." Mad servers, also called "false tickers," are servers that don't know they are serving incorrect time. Servers normally express, along with the time, an opinion of whether or not their time is correct. A mad server will say its time has been verified when in fact it hasn't.

There are times, however, when your machine cannot tell the difference between a mad server and a genuine correction of several minutes or even several years. For example, right after rebooting, your machine is dependent on the built-in real-time clock, which runs on a battery. A problem with the real-time clock could yield a date of January 1, 1980 (a common value for older BIOSes). When this happens, you don't want Domain Time to reject the correction.

In general, Domain Time overrides the maximum disparity when it has reason to doubt its own time. In automatic mode (the default), Domain Time will accept any amount of correction right after startup, when a user or process changes the time manually, or when the administrator asks the machine to sync (either from the control panel applet, dtcheck, or Domain Time II Manager).

You may add a registry value called Override Max Disparity to control this behavior:

• Server
• Full Client
  
• Thin Client