If not present, the daemon detaches from the controlling terminal and proceeds autonomously. If one or more -d switches are present, the daemon does not detach and generates special output useful for debugging. In general, interpretation of this output requires reference to the sources. However, a single -d does produce only mildly cryptic output and can be very useful in finding problems with configuration and network troubles. With a little experience, the volume of output can be reduced by piping the output to grep and specifying a keyword, such as receive or clock of the trace you want to see.
Some problems are immediately apparent when the daemon first starts running.
Other problems are apparent in the system log file. The log file should show the startup banner, some cryptic initialization data, and the computed precision value. The next most common problem is incorrect DNS names. Check that each DNS name used in the configuration file responds to the Unix ping command. When first started, the daemon normally polls the servers listed in the configuration file at 64-second intervals.