CenterClick NTP200 and NTP250 Documentation - Admin Console


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The Admin Console

All configuration of the NTP200/NTP250 is performed using the Admin console. This can be accessed using the USB console or by SSH remotely.

The physical USB console does not require authentication, however SSH access does. By default SSH is disabled.

NTP250 documentation at
Console Commands:
  show info               System Info
  show ntp                NTP Status
  show ntp details        NTP Details
  show ntp clients        NTP Clients
  show ntp acls           NTP Access Control
  show ntp bcast          NTP Broadcast/Multicast
  show ntp backup         NTP Servers/Pools
  show gps                GPS Status
  show network            Network Status
  show services           Show Services
  show localization       Show Timezone and Units
  conf network            Configure Network
  conf services           Configure Services
  conf ntp acls           Configure NTP Access Control
  conf ntp bcast          Configure NTP Broadcast/Multicast
  conf ntp backup         Configure NTP Servers/Pools
  conf localization       Configure Timezone and Units
  reboot                  Reboot
  shutdown                Shutdown
  no conf                 Reset settings to defaults [reboots]
  upgrade                 Upgrade software
  exit                    Logout


Basic Status

Use the 'show info' command to see system, power, and CPU status:

NTP250> show info
Model:         NTP250
SN:            101
Software       1.33
DC Power:      9.40
PoE Power:     good
Power:         redundant
CPU Temp:      95.0 F
Temperature:   good
Memory:        100.4 / 512 MB
CPU:           2.5%
Uptime:        2:40


Use the 'show ntp' command to see NTP status:

NTP250> show ntp
Time:          2021-11-10 13:47:11 EST
NTP Status:    good
NTP Stratum:   1
PLL Freq:      -29.4984 ppm
Clock Jitter:  0.001 msec
System Jitter: 0.001347 msec
Pending Leap:  none
RX Packets:    6.47 per minute


Use the 'show ntp details' command to see NTP details. This shows the output of 'ntpq -c peers -c sysinfo -c kerninfo -c iostats -c sysstats':

NTP250> show ntp details
NTP Details:
     remote           refid      st t when poll reach   delay   offset  jitter
o127.127.22.0    .PPS.            0 l   14   16  377    0.000    0.000   0.001
*    .GPS.            7 l   61   64  377    0.000   -2.308   1.563 .POOL.          16 p    -   64    0    0.000    0.000   0.000    .PPS.            1 u    6   64  377   57.795   -6.642   0.251    3 u    8   64  377   76.940   -0.741   0.098     2 u   13   64  377   78.299   -0.361   1.030   2 u   75   64  176  105.222   -1.770   4.348

associd=0 status=0115 leap_none, sync_pps, 1 event, clock_sync,
system peer:
system peer mode:   client
leap indicator:     00
stratum:            1
log2 precision:     -21
root delay:         0.000
root dispersion:    1.780
reference ID:       PPS
reference time:     e5369237.b7a92b3a  Wed, Nov 10 2021 13:47:19.717
system jitter:      0.001490
clock jitter:       0.001
clock wander:       0.000
broadcast delay:    -50.000
symm. auth. delay:  0.000

associd=0 status=0115 leap_none, sync_pps, 1 event, clock_sync,
pll offset:            -0.000296
pll frequency:         -29.4985
maximum error:         0.008
estimated error:       1e-06
kernel status:         pll nano
pll time constant:     4
precision:             1e-06
frequency tolerance:   500
pps frequency:         0
pps stability:         0
pps jitter:            0
calibration interval   0
calibration cycles:    0
jitter exceeded:       0
stability exceeded:    0
calibration errors:    0

time since reset:       424254
receive buffers:        10
free receive buffers:   9
used receive buffers:   0
low water refills:      1
dropped packets:        0
ignored packets:        0
received packets:       641511
packets sent:           810171
packet send failures:   0
input wakeups:          1069260
useful input wakeups:   645306

uptime:                 424254
sysstats reset:         424254
packets received:       641512
current version:        29460
older version:          14630
bad length or format:   0
authentication failed:  0
declined:               0
restricted:             0
rate limited:           1572
KoD responses:          551
processed for time:     0


Note that the 127.127 IP addresses are NTP's way of using a reference clock such as the GPS source.

Use the 'show ntp clients' command to see the NTP client list sorted by IP address:

NTP250> show ntp clients
NTP Clients:
Client Count:      39
                                     ip  last          rx count  tx count  alert
---------------------------------------  ------------  --------  --------  ------
                    16 hr ago     5         5         
                    13 hr ago     5         5         
                    33 sec ago    6909      6909      
                    32 sec ago    6909      6909      
                    22 hr ago     5         5         
                    14 hr ago     5         5         
                    43 min ago    492       246       
                    42 min ago    2831      2339      
                    15 sec ago    6909      6909      
                    3 sec ago     6909      6909      
                    7 sec ago     6909      6909      
                    1118 sec ago  305       305       
                    3 hr ago      10        10        
                    23 hr ago     5         5         
                    28 min ago    259       259       
                    28 min ago    247       247       
                    28 min ago    231       231       
                   57 min ago    122       122       
                   403 sec ago   261       261       
                   523 sec ago   262       262       
                  251 sec ago   432       432       
                  24 hr ago     33        22        sleep
                  72 min ago    223       150       sleep
                  551 sec ago   249       166       
                  2 days ago    63        42        sleep
                  2 days ago    402       268       sleep
                     2620:9a:e000:12::1  260 sec ago   419       419       
                     2620:9a:e000:13::1  737 sec ago   418       418       
                     2620:9a:e000:14::1  496 sec ago   419       419       
                     2620:9a:e000:80::4  14 hr ago     5         5         
                    2620:9a:e000:100::2  896 sec ago   474       474       
                   2620:9a:e000:1011::1  73 sec ago    607       607       
                  2620:9a:e000:1022::85  123 sec ago   499       499       
                  2620:9a:e000:1022::86  701 sec ago   615       615       
  2620:9a:e000:1025:d92e:f5c7:2da8:1a64  3 days ago    1         1         sleep
                  2620:9a:e000:1060::10  27 sec ago    4104      4104      
                   2620:9a:e000:1061::1  251 sec ago   432       432       
                   2620:9a:e000:1063::2  172 sec ago   559       559       
   2620:9a:e000:1063:250:b6ff:fecd:5aed  30 hr ago     147       147       sleep


Use the 'show gps' command to see the GPS status

NTP250> show gps
GPS Mode:      3d-fix
Leap Seconds:  18
Latitude:      xx.xxxxxxx +/-37ft
Longitude:     xx.xxxxxxx +/-33ft
Altitude:      xxx.xxft +/-20ft
Satellites:    34 seen, 17 used
  List:        GNSSID   SVID    PRN     EL      AZ      SS      USED
               GPS      1       1       XXX     XXX     34      1
               GPS      3       3       XXX     XXX     0       0
               GPS      6       6       XXX     XXX     0       0
               GPS      7       7       XXX     XXX     26      1
               GPS      8       8       XXX     XXX     28      1
               GPS      13      13      XXX     XXX     12      0
               GPS      14      14      XXX     XXX     17      1
               GPS      17      17      XXX     XXX     24      1
               GPS      19      19      XXX     XXX     22      1
               GPS      21      21      XXX     XXX     26      1
               GPS      22      22      XXX     XXX     0       0
               GPS      30      30      XXX     XXX     30      1
               SBAS     133     46      XXX     XXX     0       0
               SBAS     135     48      XXX     XXX     0       0
               SBAS     138     51      XXX     XXX     34      1
               Galileo  1       301     xxx     xxx     8       0
               Galileo  13      313     xxx     xxx     22      1
               Galileo  15      315     xxx     xxx     20      1
               Galileo  18      318     xxx     xxx     25      0
               Galileo  21      321     xxx     xxx     19      1
               Galileo  26      326     xxx     xxx     24      1
               Galileo  27      327     xxx     xxx     24      1
               Galileo  30      330     xxx     xxx     0       0
               GLONASS  6       70      XXX     XXX     0       0
               GLONASS  7       71      XXX     XXX     0       0
               GLONASS  12      76      XXX     XXX     16      0
               GLONASS  13      77      XXX     XXX     0       0
               GLONASS  14      78      XXX     XXX     0       0
               GLONASS  15      79      XXX     XXX     0       0
               GLONASS  17      81      XXX     XXX     20      1
               GLONASS  22      86      XXX     XXX     0       0
               GLONASS  23      87      XXX     XXX     25      1
               GLONASS  24      88      XXX     XXX     27      1
               GLONASS  25      89      XXX     XXX     0       0


Use the 'show network' command to see current network configuration. In the example below, DHCPv4 and DHCPv6 are used to obtain pool addresses and both DNSv4 and DNSv6 settings.

NTP250> show network
Status:        good
Link:          link-up
MAC Addr:      xx:xx:xx:xx:xx:xx
Addressing:    IPv4: auto, IPv6: auto
IPv4 Addr:
IPv4 GW:
IPv6 Addr:     2620:9a:e000:1061:57cc:899c:86e1:a19b/64, 2620:9a:e000:1061::8:62/128, fe80::3991:4d79:aab9:32a4/64
IPv6 GW:       fe80::1061
DNS: ,, 2620:9a:e000::1, 2620:9a:e000:1060::10
LLDP Neighbor: mac e0:d1:73:f4:27:0a, core-sw1, ifname gi2/1/15


Configuring the Network

Both IPv4 and IPv6 are supported and, by default, DHCPv4 and DHCPv6/Autoconf6 are used to obtain network addresses automatically.

NTP250> conf network
Configuring Network...

Network Commands:
  exit                                   Exit Network Menu
  ip4 auto                               IPv4 DHCP [reboots]
  ip4 static IP/MASK GW { DNS1,DNS2 }    IPv4 Static (DNS optional) [reboots]
  ip6 auto                               IPv6 Autoconf/DHCP [reboots]
  ip6 static IP/MASK GW { DNS1,DNS2 }    IPv6 Static (DNS optional) [reboots]

  ip4 static,
  ip6 static 2001:db8:74::10/64 2001:db8:74::1 2001:db8::59,2001:db8::32


IPv4 and IPv6 are configured independently, each can be dynamic or static. When configured for DHCP, IP address and DNS settings are learned automatically. For IPv6 router advertisements are used to determine stateful/stateless mode and DHCPv6 used if needed to obtain pool or static binding IP addresses, and DNSv6 information.

The device will function correctly in legacy IPv4-only, dual IPv4/IPv6, or IPv6-only environments.

Configuring Services

By default, HTTP is enabled; SSH, HTTPS, and location privacy are disabled; and automatic upgrades are set to check-only. You can use the Services menu to configure each. The exact list of commands vary depending on your current configuration.

NTP250> conf services
Configuring Services...

Service Commands:
  exit                                  Exit Service Menu
  no http                               Disable HTTP interface
  https                                 Enable HTTPS interface
  no client dns                         Disable Client DNS Lookups [reboots]
  location privacy                      Enable Location Privacy on HTTP
  auto upgrade install                  Check for upgrades, and install
  no auto upgrade                       Don't check for upgrades
  ssh                                   Enable SSH


For details on configuring HTTPS, see the detailed HTTPS guide.

For details on configuring SSH authentication, see the detailed SSH guide.

Client DNS lookups can be disabled or enabled. Results will be displayed on the clients webpage, CSV, and JSON, but not on the console.

Note that HTTP location privacy is disabled by default, that meaning anyone who can access the HTTP interface can determine the device location. When HTTP location privacy is enabled the location data is unavailable on the HTTP interface however it is still shown on the admin console.

Automatic upgrades can be set to one of 3 states: 'no auto upgrade', 'auto upgrade check-only', or 'auto upgrade install' which respectivly don't check for upgrades at all, checks for but does not install, or both checks for and automatically installs firmware. The default is to check but not install.
If enabled, the check will occur within about an hour after boot and then daily between 1AM and 2AM in the configured timezone. The results of the check will be displayed on the main webpage.

Configuring NTP Access Control

Access Controls allow you to further open or restrict NTP operations based on a source IP/MASK.

There are 3 operations that can be allowed or denied:

  1. sync: the ability to synchronize (i.e. the normal NTP operation)
  2. query: the ability to query the appliance over NTP packets with 'ntpq' or 'ntpdc'
  3. ratelimit: rate limits for misbehaving clients and DoS attacks.

By default, all IPs can synchronize and are subject to rate limits as shown in the menu below:

NTP250> conf ntp acls
Configuring Access Control...

Current Access Controls:                       sync ratelimit
  ::/0                            sync ratelimit

  Access Control Commands:
  exit          Exit Access Control Menu
  D IP/MASK     delete entry
  S IP/MASK     clients can: sync with ratelimit (default)
  R IP/MASK     clients can: sync with nolimit
  Q IP/MASK     clients can: sync and query with ratelimit
  U IP/MASK     clients can: sync and query with nolimit
  B IP/MASK     clients are blocked

  R          # These hosts are not subject to rate limiting
  Q 2001:db8:522:74::/64    # These hosts can query with ntpq and ntpdc
  B          # This host is banned


Using the various commands above you can add, modify, or remove entries to allow specific hosts or networks.

Note that IP/MASK entries are hierarchical, for example, you can create an entry for 2001:db8:22::/48 that allows query, another entry for 2001:db8:22:7::/64 that has both query and no rate limit, and another entry for 2001:db8:22:7::99/128 that is blocked entirely.

The default entries ( and ::/0) cannot be removed, however you can modify them.

Configuring NTP Broadcast/Multicast

Sending NTP to Broadcast and/or Multicast addresses is disabled by default but can be configured as described below.

NTP250> conf ntp bcast
Configuring NTP Broadcast/Multicast...

Current NTP Broadcast/Multicast:

Broadcast/Multicast Commands:
  exit          Exit Broadcast/Multicast Menu
  send IP       add broadcast/multicast server entry
  no send IP    delete broadcast/multicast server entry

  send      # RFC919: limited broadcast
  send          # RFC919: all hosts on the local IP net
  send            # RFC5905 Section 8
  send ff02::101            # RFC5905 Section 8


For IPv4, you can send to the limited broadcast (, your local network broadcast, or to the IPv4 NTP multicast address

For IPv6, you can send to one of the IPv6 NTP multicast addresses such as ff02::101 for link-local scope.

You can configure any number of broadcast/multicast addresses and packets will be sent to all of them at the default 64-second interval.

For further information on NTP multicast address assignments see IANA IPv4 multicast assignments and IANA IPv6 multicast assignments. You are not restricted to sending to the standard IP addresses and can enter any IP you would like if needed.

Configuring NTP Servers/Pools

You can configure the device to also sync to other NTP servers or pools of servers to act as a backup in case the GPS signal is weak or lost. Under normal operation the GPS source has priority and the backup servers and pools will only be used if the GPS signal is weak or lost.

NTP250> conf ntp backup
Configuring NTP Backup Servers/Pools...

Current NTP Backup Servers/Pools:

Backup Servers/Pools Commands:
  exit             Exit Backup Servers Menu
  server IP/DNS    add backup server entry
  no server IP/DNS delete backup server entry
  pool DNS         add backup pool entry
  no pool DNS      delete backup pool entry

  server            # a local server on your network
  server     # a local server on your network
  pool        # a public pool of servers
  pool    # a public pool of servers


By default the pool '' is configured, you can remove, replace, or add additional servers or pools if you'd like

The difference between a server and a pool is that servers are static where as pools are more flexible allowing multiple and changing IP lookups to a DNS name.
For pools, the resolved IPs are added and removed dynamically on the fly as needed. See for a list of pools in your region.
Note that servers by DNS names are only resovled on startup of the appliance.

Setting the Timezone and Units

By default the timezone is set to UTC and units are in feet and fahrenheit, you can change this on the admin console.

NTP250> conf localization
Configuring Localization...

Timezone:            Etc/UTC
Length units:        ft
Temperature units:   f

Localization Commands:
  exit             Exit Localization Menu (and Reboot if needed)
  timezone         Configure timezone [reboot on exit]
  units meters     Set units of length [reboot on exit]
  units celsius    Set units of temperature [reboot on exit]


When choosing a timezone, you will be asked to pick from a wide variety of zones, for example below the zone is changed to 'America/New_York'. Note that the timezone is for display only, the GPS and NTP protocols do not make use of a timezone.

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