NTPDC(8) System Manager's Manual NTPDC(8)
ntpdc - monitor operation of ntp daemon
ntpdc [-n] [-v] hosts...
ntpdc sends an INFO_QUERY packet to an ntp daemon running on the given hosts. Each daemon responds with information about each of its
peers, which ntpdc formats on the standard output.
Normally, the name of the responding host and its peers are printed. The -n switch disables this, printing only internet addresses.
Default is a terse, table-style report. The -t switch generates an alternate form of the terse report. The -v switch generates a verbose
A typical terse report looks like:
(rem) Address (lcl) Strat Poll Reach Delay Offset Disp
-umd1 18.104.22.168 1 64 266 3.0 -65.0 0.0
*DCN1.ARPA 22.214.171.124 1 256 332 155.0 -4.0 0.0
126.96.36.199 188.8.131.52 2 64 367 -16.0 -61.0 0.0
idunno.Princeto 184.108.40.206 3 64 252 60.0 -53.0 0.0
leo 220.127.116.11 2 64 275 4.0 -273.0 1536.2
The alternate form is only slightly different; it looks like:
Address Reference Strat Poll Reach Delay Offset Disp
-umd1 WWVB 1 64 266 3.0 -65.0 0.0
*DCN1.ARPA WWVB 1 256 332 155.0 -4.0 0.0
18.104.22.168 umd1 2 64 367 -16.0 -61.0 0.0
idunno.Prince trantor 3 64 252 60.0 -53.0 0.0
leo umd1 2 64 275 4.0 -273.0 1536.2
Fields are interpreted as follows:
- or *:
The - mark indicates a pre-configured peer (mentioned in ntp.conf). the * mark shows which pre-configured peer (if any) is cur-
rently being used for synchronization.
The remote host name or internet address of a peer.
The "local" host as specified as an argument to ntpdc.
The reference time source being used for synchronization by the peer.
Strat: The stratum level of the peer (as perceived by the local host).
Poll: Current polling interval in seconds for this peer.
Reach: Octal value of a shift register indicating which responses were received from the previous 8 polls to this peer (see RFC-????).
Delay: Round-trip delay in milliseconds for this peer as of the latest poll.
Disp: Current value of dispersion (see RFC-????) in milliseconds for this peer.
When the -v flag is given a series of verbose reports are presented. A typical one looks like this:
Neighbor address 22.214.171.124 port:123 local address 126.96.36.199
Reach: 0376 stratum: 1 poll int(HPI): 10 precision: -10
Sync distance: 0 disp: 0.014000 flags: 0 leap: 0
Reference clock ID: WWV timestamp: a7c2832e.6f9d0000
Poll int(MPI): 10 threshold: 1024 timer: 1024 send: 266 received: 192 samples: 9
Delay(ms) 1144.00 1296.00 1118.00 1115.00 1225.00 1129.00 1086.00 1087.00
Offset(ms) 19.00 92.00 -17.00 12.00 41.00 4.00 -1.00 -14.00
delay: 1086.000000 offset: -1.000000 dsp 0.014000
Fields are interpreted as follows:
The address and port number of this neighbor, followed by the local address.
Reachability in response to last 8 polls (octal value of shift register)
poll interval: time
The precision of this clock, given in seconds as a power of 2. e.g A clock derived from the power line frequency (60 Hz) has a pre-
cision of 1/60 second (about 2^-6) and would be indicated by a precision of -6.
Syn distance: 0
Synchronizing distance. Always zero in the current implementation.
The leap second indicator. Non-zero if there is to be a leap second added or subtracted at the new year.
Reference clock ID: [address]
Poll interval: time
The number of ntp packets sent to this neighbor.
The number of ntp packets received from this neighbor.
Delay and Offset
The round-trip delay and clock offset for the last eight ntp packet exchanges. If there are fewer than eight valid samples, the
delay field will be zero.
delay: avg-delay offset: avg-offset dsp ???
Average delay, offset, and dispersion calculated from the above samples. Meanings...???
Probably a few. Report bugs to Louis A. Mamakos (firstname.lastname@example.org).
RFC-???? Network Time Protocol(1), Dave Mills and ...
10 March 1989 NTPDC(8)