ONC+ Developer's Guide

Time Synchronization

Kerberos uses the concept of a time window in which its credentials are valid. It does not place restrictions on the clocks of the client or server. The client is required to determine the time bias between itself and the server and compensate for the difference by adjusting the window time specified to the server. Specifically, the window is passed as an argument to authkerb_seccreate(); the window does not change. If a timehost is specified as an argument, the client side gets the time from the timehost and alters its timestamp by the difference in time. Various methods of time synchronization are available. See the kerberos_rpc(3KRB) man page for more information.