What does ntpq command do?
The ntpq command uses NTP mode 6 packets to communicate with the NTP server and can query any compatible server on the network which permits it. The ntpq command makes one attempt to retransmit requests, and will time-out requests if the remote host does not respond within a suitable time.
What does * mean in ntpq output?
current synchronization source
Re: Interpreting NTPQ output * indicates the current synchronization source. # indicates that the host is selected for synchronization, but distance from the host to the server exceeds the maximum value. o indicates that the host is selected for synchronization, and the PPS signal is in use.
What is Refid in ntpq?
NTP’s Reference ID, or REFID, identifies the source of time in a timestamp or time packet. In NTP packets sent over the network the REFID is used to identify the “system peer”, and in the long-term general case its fundamental purpose is to prevent a one-degree timing loop.
What is ntpq command in Linux?
ntpq is an open source and free utility available on Linux Based Servers that monitors the NTP daemon NTPD and queries its performance. This is one of the frequently used command in most of the Organizations to check the NTP server performance.
What is offset value in ntpq?
Offset: Offset generally refers to the difference in time between an external timing reference and time on a local machine. The greater the offset, the more inaccurate the timing source is. Synchronised NTP servers will generally have a low offset. Offset is generally measured in milliseconds.
What is drift file in NTP?
The driftfile entry in /etc/ntp. conf tells ntpd the name of the file where it can find and store the clock drift, also known as frequency error, of the system clock. If the file exists at startup, it is read and the value is used to initialize ntpd’s internal value of the frequency error.
What is stratum and jitter in NTP?
A stratum 1 NTP server obtains time from an external timing reference. Stratum 2 devices obtain time from stratum 1 devices and pass timing information to the next level and so on. Jitter: The jitter associated with a timing reference indicates the magnitude of variance, or dispersion, of the signal.
What is ntpdate command?
Description. The ntpdate command sets the local date and time by polling the NTP servers specified to determine the correct time. It obtains a number of samples from each server specified and applies the standard NTP clock filter and selection algorithms to select the best of the samples.
What is burst in NTP?
BURST sends a burst of eight packets when the server is reachable, and is used to accurately measure jitter with long poll intervals. IBURST sends a burst of eight packets when the server is unreachable (tries to find out if a host is reachable), and then shorten the time until the first sync.
What is offset value in NTP?
How to use force ntpq in interactive mode?
Force ntpq to operate in interactive mode. Prompts will be written to the standard output and commands read from the standard input. Output all host addresses in dotted-quad numeric format rather than converting to the canonical host names. Print a list of the peers known to the server as well as a summary of their state.
ntpq [-inp] [-c command] [host] […] Description ntpqis used to query NTP servers which implement the recommended NTP mode 6 control message format about current state and to request changes in that state. The program may be run either in interactive mode or controlled using command line arguments.
What is the default response time for ntpqretries?
Specify a timeout period for responses to server queries. The default is about 5000 milliseconds. Note that since ntpqretries each query once after a timeout, the total waiting time for a timeout will be twice the timeout value set. Control Message Commands
How do I get a list of Peers in NTP?
ntpqcan also obtain and print a list of peers in a common format by sending multiple queries to the server. If one or more request options is included on the command line when ntpqis executed, each of the requests will be sent to the NTP servers running on each of the hosts given as command line arguments, or on localhost by default.